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2017/2018 > EOS 170 III > Flashcards

EOS 170 III Flashcards

1
Q

when was Fort MacMurray 2016 fire extinguished

A

after 2017 snow melt

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2
Q

what is a fire hazard

A

a woodland fire directly impacts humans

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3
Q

examples of how fires impact human activity

A
  • wildland-urban interference
  • threaten economic activity
  • forestry, mining, pipelines, communications
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4
Q

how does forestry impact fire hazard

A

Forestry invests in monoculture tree farms, primarily pine

-monoculture easy to burn

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5
Q

Physical fire hazard modelling

A

relies on understanding of physical processes

  • must know fuels, terrain, weather
  • use radiation, convection
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6
Q

empirical modelling of fire hazard

A

statistical relationship btw observed fire behaviour and input variables

  • do not have to rely on physics
  • relate behaviour to observed
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7
Q

physical modelling advantages

A

widespread applicability

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8
Q

empirical modelling advantages

A

-easy to implement

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9
Q

physical modelling disadvantage

A

-must have thorough understanding of physical processes

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10
Q

empirical modelling disadvantage

A
  • model tied to calibration data/area

- not good widespread (highly variable env’ts)

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11
Q

fire behaviour modelling vectors

A
  • terrain / topography
  • weather
  • fuel
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12
Q

Fire behaviour modelling, topography

A
  • most stable
  • slope gradient
  • aspect
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13
Q

Fire behaviour modelling, weather

A
  • standard meteorological conditions

- may add historic data

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14
Q

Fire behaviour modelling, fuel

A
  • most complez
  • species, forest structure, complexity
  • coarse woody debris (forest floor)
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15
Q

slope gradient

A

first derivative of elevation

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16
Q

aspect

A

direction of maximum slope

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17
Q

SWI

A

soil wetness index

-complex metric combining upslope drainage area and gradient

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18
Q

fuel typing

A
  • vegetation type (grassland, deciduous, etc)

- stand structure (height, density, leaf area, height, age)

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19
Q

Fire fuel mapping

A
  • MODIS, optical sensor, 250m res
  • LANDSAT, os, 30m res
  • RADARSAT, microwave sensor, variable res
  • Airborne Imaging RADAR, ms, variable res
  • LiDAR
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20
Q

LiDAR

A

Light Detection and Ranging

  • pulsed laser beam
  • high frequency
  • measures very detailed heights
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21
Q

Modelling caveats

A
  • output detail = input detail

- output accuracy - product of input variable errors

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22
Q

weather

A
  • meteorological conditions
  • short-term processes
  • localized
  • temperature, precipitation, wind at a given time and place
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23
Q

climate

A
  • meteorological conditions
  • T, precip, wind that characteristically prevail in a region
  • long-term processes
  • regional
  • statistics of weather
  • weather averaged over t for a region
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24
Q

weather changes on short-long t scales due to

A
  • meteorological conditions (moving air masses)
  • daily T changes
  • seasonal variation
  • climate change
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25
Q

Natural climate change

A
  • polar continents
  • continents aligned N-S
  • variations in solar heating/ sun spots (11-110 yr cycles)
  • Milankovitch cycles
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26
Q

Natural climate change, polar continents

A

= increased albedo = lower global T

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27
Q

Natural climate change, N-S aligned continents

A

= ocean circulation bringing warm water to high lats = increased precip. – increased glaciation - lower global T

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28
Q

Milankovitch cycles

A
  • variation in E’s orbital properties
  • eccentricity
  • tilt
  • wobble
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29
Q

atmospheric circulation cells

A
  • 3 cells per hemisphere

- driven by solar E, cold air sinking, weak horizontal P gradient at equator

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30
Q

circulation cell closest to equator

A

Hadley cell

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31
Q

Hadley cell

A
  • warm air rises at eq.
  • atmospheric instability – thunderstorms, latent heat released
  • latent heat drives hadley cell
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32
Q

latent heat

A
  • E release as water vapour changes to liquid water droplets

- surrounding air becomes warm and moist

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33
Q

Polar front

A
  • typically 30º
  • surface high P causes ground air to diverge
  • air mass descends to replace diverging air
  • clear skies, dry air
  • warm moist vs cold dry = gradient = front at 45º
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34
Q

coriolis

A
  • movement deflected to right in NH
  • increases w/ objects horizontal speed
  • zero at equator, increases towards poles
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35
Q

eccentricity

A
  • changes in earths orbit
  • 100,000 yr cycle
  • more elliptical = larger variability in season length
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36
Q

large eccentricity coincides with

A

broad glacial cycles

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37
Q

orbital tilt

A
  • change in inclination of earths spin axis
  • 41,000 yr cycle
  • 21.5 - 24.5
  • currently 23.5
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38
Q

greater orbital tilt

A
  • greater seasonal extremes
  • colder winter, warmer summer
  • decreased glaciation
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39
Q

orbital wobble

A

change in spin-axis direction

  • 19-23,000 yr cycle
  • precession of the equinoxes
  • changes extremeness of seasons
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40
Q

current orbital wobble

A

E closest to sun during NH winter - milder winters and summers in N than S

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41
Q

greenhouse effect

A
  • INSOLATION as shortwave radiation heats E
  • longwave radiates back to space
  • greenhouse gases capture longwave (IR, heat) preventing loss
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42
Q

Earths T without greenhouse gases

A

-18º (average)

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43
Q

Earth’s T with GHGs

A

16º (average)

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44
Q

Mars T

A

-53º (no GHG)

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45
Q

Venus T

A

480º (excess GHG)

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46
Q

greenhouse gases

A 
H2O
CO2
CH4
N2O
O3
CFCs
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47
Q

anthropogenic GHGs

A
  • burning fossil fuels (CO2)
  • decomp, cattle, rice (CH4)
  • fertilizer, auto combustion (N2O)
  • undustrial gases (O3, smog)
  • coolents (CFCs)
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48
Q

Climate change in BC

A
  • Pacific too warm for salmon
  • increased wildfires and length of fire season
  • more winter precip., more spring floods, landslides, avalanche
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49
Q

4/5 of most costly Canadian disasters 1900-2005

A

drought

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50
Q

top 3 deadliest Canadian disasters

A
  1. influenza, 1918-1925, 50,000 deaths
  2. halifax explosion, 1917, 1900 deaths
  3. heat wave, 1936, 1200 deaths
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51
Q

drought can cause

A
  • economic loss: crops, pastures, livestock, water

- famine, death

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52
Q

common cause of drought

A
  • entrenched high pressure ridge
  • descending warm dry air mass desiccates land
  • high P ridge block moist air flow
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53
Q

‘Dirty 30’s’

A
  • severe drought during 1930s
  • 40% less rainfall
  • non-drought resistant crops died, did not protect erosion
  • immense dust storms blew away top soil
  • millions of acres of farmland ruined
  • thousands of livestock died
  • 1/4 million people abandoned farms
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54
Q

heat-related deaths in Canada

A

1940s - 50/yr
1970s - 7/yr
present- none

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55
Q

1936 Canada heat wave

A
  • 1180 deaths
  • 44º in Manitoba, Ontario, 50º in Kansas
  • night-time min. >25º
  • rail lines warped
  • road surfaces melted in >65º sun
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56
Q

2003 European heat wave

A
  • 35000 died
  • worst heat wave in 150 yrs
  • 10º hotter than 2001
  • 14,800 deaths in France
  • 7000 Germany
  • 4000 Spain
  • 4000 Italy
  • 2000 UK
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57
Q

2003 European heat wave, France

A
  • 14,800 deaths
  • no AC, nights usually cool
  • stone/concrete homes - radiate absorbed heat and cool at night
  • high night min.s prevented cooling
  • early Aug, many away on Vacation, left elderly home alone to parish
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58
Q

heat wave predictions

A
  • more frequent, more severe
  • exacerbated w/ urbanization
  • AC reduces hazard
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59
Q

thunderstorms kill, injure, damage by

A
  • lightning
  • fires
  • hail
  • wind
  • rain, flash floods
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60
Q

thunderstorm stages

A

cumulus
mature
dissipating

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61
Q

highest average number of days/yr w/ thunderstorms

A

southern interior of country

  • 25 around Edmonton, regina, toronto
  • least near coasts and in North
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62
Q

lightning worldwide

A

100 strikes/s

9 million strikes/day

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63
Q

lightning in Canada

A 
3 mill flashes/yr
10 deaths/yr
125 injuries/yr
3 light. fire deaths/yr
-male deaths 5X fm
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64
Q

lightning deaths

A
  • more in CAD/US than any other natural hazard
  • less publicized b/c smaller groups, damage
  • death rate decreasing
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65
Q

lightning cause

A
  • updraft/downdraft collisions btw super-cooled water and ice crystals cause electric charge separation
  • collision transfer + charge to ice, - to water-ice mixture
  • updraft drive ice up = + accumulation at top
  • gravity pulls water-ice down = - accumulation at bottom
  • induces opposite charge accumulation in ground
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66
Q

water-ice mixture in thundercloud

A

graupel

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67
Q

Lightning strike is

A

-electrical discharge btw opposite charge accumulations

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68
Q

lightning strikes occur

A
  • btw cloud and ground
  • btw clouds
  • w/i cloud
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69
Q

lightning speed

A

> 10,000 km/s

creates T 30,000º

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70
Q

thunder

A

rapid thermal expansion of air from 30,000º T

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71
Q

lightning groundstroke

A

-connection of stepped leader and positive streamer establishes channel of ionized air = low resistance path

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72
Q

stepped leader

A

(-)electrons stream from cloud-Earth in 50m jumps (stepped leader)

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73
Q

postive streamer

A

-as near E, positive streamer initiated upward, connecting 50m above surface

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74
Q

lightning groundstroke, return stroke

A

high-current flow of +charge from E-cloud along ionized path = bright flash

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75
Q

what to do in case of lightning

A
  • follow warnings
  • avoid elevated, exposed location
  • get into car, don’t touch sides
  • crouch down on ground
  • stay 5m away from others
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76
Q

lightning 30/30 rule

A
  • if time btw lightning and thunder less than 30s, take shelter (30s = 10km)
  • wait 30min after last lightning flash before leaving shelter
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77
Q

what not to do in lightning

A
  • shelter under tree, near metal fence, in tent w/ poles, in cave
  • walk under power lines, along rails, highway w/ guards
  • go swimming
  • stay near open window
  • use electric devices
  • wash dishes, take shower
  • use land-lines
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78
Q

Hail

A
  • layered ice ball formed in thunderstorms w/ large vertical T contrast
  • cycle up/down through cloud until too heavy
  • add most of mast
  • hail clouds often dark w/ green tinge
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79
Q

hail distribution

A
  • require cold air at elevation
  • most common in prairies, central BC
  • AB ‘hailstorm alley’ lee side of rockies - highest hail rates in world
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80
Q

hailstone sizes

A
  • compared to common objects
  • CD 128mm
  • softball 114mm
  • Grapefruit 102mm
  • baseball 70mm
  • Egg 50mm
  • golfball 44mm
  • marble 13mm
  • pea-size 6.4mm
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81
Q

Hail terminal velocity

A
  • max speed
  • balance of g acceleration vs air drag
  • varies by diameter
  • 1cm = 9m/s (32km/hr)
  • 8cm = 48m/s (170km/hr)
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82
Q

largest documented hailstone

A

0.75kg

28cm diameter

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83
Q

hail damage

A
  • rarely injures or kills
  • one of most expensive natural hazards damages:
  • cars, aircraft, skylights, glass grooves, kills livestock, destroys crops
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84
Q

Canada’s deadliest tornadoes

A

Regina, 1912, 28 deaths
Edmonton, 1987, 27d
Windsor, 1946, 17d

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85
Q

most tornadoes in the world

A

US - 1000/yr
Canada- 100/yr
Europe 250/yr

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86
Q

most canadian tornadoes

A

south end of province and BC interior

-very highest in S Ont

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87
Q

most tornadoes in US

A

E side of country

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88
Q

tornado classification

A

Fujita scale
-6-level scale
-according to storm damage, wind speed
F0 - F5

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89
Q

F0

A

light damage

  • 65-115km/h wind
  • 28% of all tornadoes
  • width up to 15m
  • damages grooves, signs, antennas
  • break twigs, branches
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90
Q

F1

A

moderate damage

  • 117-180km/hr
  • 39% of all tornadoes
  • width 16-50m
  • length 1-5km
  • damage weak structures
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91
Q

most intense atmospheric phenomena

A

Tornado

500km/hr wind

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92
Q

F2

A

considerable damage

  • 181-253 km/h
  • 5-16kmlong, 50-160m wide
  • destroy mobile homes, tip vehicles, uproot large trees
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93
Q

F3

A 
severe
254-332 km/h
-6%
-16-50km long, 160-500m wide
-entire roofs, levels trees, lift heavy vehicles
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94
Q

F4

A 
devastating
333-418km/hr
-2%
-160km long, 1500m wide
-well-built building flattened, tossed cars, tree havens, trains flipped
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95
Q

70% of all tornado deaths

A

F4, F5

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96
Q

F5

A 
incredible
>419km/h wind
-less than 1%
-more than 160km long, 1500-5000m wide
-few seconds but terrifying strength
-buildings disintegrated, rubble carried far, steel damaged, heavy vehicles thrown up to 2km
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97
Q

tornado formation

A

3 air masses in different direction cause rotation w/i thunderstorm cloud

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98
Q

tornado forming air masses, NA

A
  1. low altitude N flow warm moist air (GoMex)
    2.mid-alt. winds to SE of cool dry air
  2. ## high alt., high -speed jet stream winds to E
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99
Q

tornado alley

A
  • US great plains, btw rockies and appalachians

- cold dry rocky air meets warm moist GoMex air, hot dry Sonoran desert air

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100
Q

required to spawn tornado

A

super-cell thunderstorm

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101
Q

super-cell thunderstorm

A

wind shear title thcloud into anvil - warm updraft separated from cool downdraft - more intense thstorm, higher change of tornado

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102
Q

single-cell thunderstorm

A

-moisture condenses from rising hot moist air, falls through cloud = cool downdraft, suppresses updraft, reduces intensity of thunderstorm and chance of tornado

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103
Q

tornado damage

A
  • buildings- blow off roofs, gutters, off foundation
  • battering from airborne projectiles
  • throw people
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104
Q

tornado safety

A
  • listen for warnings
  • cellar/ basement w/o windows
  • safe room
  • safer in a parked vehicle than mobile home
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Perfectly
105
Q

1947 super tornado outbreak

A
  • > 16 hours
  • 148 tornadoes in 13 states + Ontario
  • 6 F5s on ground >50km
  • 335 deaths
  • 1200 injuries
  • > 7500 destroyed homes
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106
Q

1987 Black Friday tornado, edmonton

A

Deadliest since 1912

  • F4, max winds 330-415km/hr
  • 40km long path, 1km wide, 1hr on ground
  • 27 killed, 300 injured, 750 homeless
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107
Q

Changing climate in canada, Natural Resources

A
  • new opportunities (North)

- awareness and action most important where clear direct relationship w/ climate (forestry, hydro)

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108
Q

Changing climate in canada, food

A
  • increased invasives, diseases
  • medium-term increase in production
  • warmer-weather crops grown further north
  • extended growing period, feeding season for livestock
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109
Q

Changing climate in canada, biodiversity

A
  • species distr. shifts
  • many species cannot adapt fast enough
  • protected areas, migration corridors imperative
  • ecological restoration/ mitigation provides resilience
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110
Q

Changing climate in canada, human health

A
  • climate-sensitive disease (lyme), vectors
  • hazards
  • new tools: heat alert, projection of vector-borne illnesses, greening urban areas
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111
Q

long-lived, straight-line wind storm associated with fast-moving severe thunderstorms

A

Derechos

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112
Q

Derechos winds

A
  • gust front/ outflow boundary
  • sustained winds
  • increased in strength behind front
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113
Q

Derechos occurrance

A
  • US warm-weather phenomenon

- mostly in summer in NH

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114
Q

Derechos cause

A

hurricane-force winds, tornadoes, heavy rain, flash floods

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115
Q

Flood:

A

overflow or accumulation of water that submerges land

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116
Q

flooding causes

A

damage to buildings, roads, bridges, sewers, vehicles

  • drowning (ppl, livestock)
  • contamination of water
  • spreads disease
  • destroys crops
  • kills trees
  • famine
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117
Q

Canada floods

A
  • few deaths (ca. 200 in 20th C), 10-15/decade

- increase since 1960s

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118
Q

Floods in canada, occurrence

A
  • every month
  • max: Spring, early summ
  • min: fall, early winter
  • every province
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119
Q

Most floods in Canada

A
  • ON, QB, NB

- few in North

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120
Q

Eliminate flood risk

A
  • move away from water
  • live near water for food, water, travel, transport, trading, irrigation, recreation, aesthetics
  • perceived value exceeds risk
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121
Q

Flood types

A
  • Hydrometeorological floods
  • Natural dams
  • rainfall flood
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122
Q

Hydrometeorological floods

A
  • caused by specific weather
  • rainfall
  • snowmelt
  • rain-on-snow
  • icejam
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123
Q

Natural dam flood

A

-obstructed water flow floods land

124
Q

catastrophic failure of natural dam

A

outburst flood

125
Q

worldwide, affects more people than any other natural disaster

A

flooding

126
Q

rainfall flood

A

-precip > infiltration + carrying capacity of streams/ rivers

127
Q

slow rainfall flood

A
  • sustained heavy rain over large are for 1+ days

- exceed runoff capacity

128
Q

flash flood

A
  • torrential rainfall over short t period (less than 6hr) and small area
  • saturate ground w/ runoff
129
Q

VI slow flood

A

2009

  • 300 homes evacuated
  • schools close
  • high tides flood Duncan
  • high tides stopped rainwater from draining
130
Q

VI 2009 flood cause

A

Pineapple express

  • several days of heavy rain
  • 250 mm in 24hrs on N island
  • 8 rivers flooded including cowichan, animo
131
Q

Pineapple express

A

warm, moist, sub-tropical P air from Hawaii = heavy rains

132
Q

canadian record flash flood

A 
Buffalo gap, SK, 1961
-254mm in less than 1hr 
Toronto, 2005
-153mm + hail 
-$500M damage
133
Q

flash flood fatalities

A

1/2 - driving

134
Q

driving flood fatalities

A
  • water 0.3 m deep can move vehicle laterally
  • water 0.6m can float car, roll or flip
  • road surface can be washed out
135
Q

snowmelt flood

A
  • most common flooding in Canada
  • generally in spring
  • water unable to penetrate frozen ground - runs over surface
  • affects large areas
136
Q

rain-on-snow flood

A
  • combines rainfall w/ snowmelt flood
  • heavy rain on snow at ca 0º
  • rain+snow cannot penetrate frozen ground
  • heavy water-saturated snow damages buildings, roofs, and cause avalanche hazard
137
Q

Icejam flood

A
  • major problem in CAD rivers
  • accumulation of ice, obstructs river flow
  • at freeze-up or break-up, worst flooding at break-up
138
Q

common icejqm sites

A
  • river bend
  • change in slope
  • bridges, piers
139
Q

rivers particularly vulnerable to icejam

A

S-> N flowing

  • S break-up sends ice N where still frozen
  • ex. St Lawrence, McKenzie, Red River
140
Q

Natural dams formed by

A
  • glaciers
  • mass movement
  • lava/ pyroclastic flow
141
Q

catastrophic failure of natural dam

A

outburst flood

142
Q

outburst flood of glacial origin

A

Jökulhlaups

-icelandic for ‘glacier-burst’

143
Q

Vatnajökull Jökulhlaup

A

-icelandic volcanism beneath Vat. icecaps maintain sub-glacial lake

144
Q

Vatnajökull Jökulhlaup, 1996

A

13day eruption filled lake w/ 4km3 of water

  • lake failed, 3.6km3 discharged in 20hrs
  • peak 55,000 m3/s (20X rate of Niagra)
  • 1000 tonne iceblocks
  • 9m of sediment
145
Q

Vatnajökull Jökulhlaup lake

A

Grimsvötn

146
Q

Vatnajökull Jökulhlaup damages

A
  • 6km of highway
  • power, phone lines
  • 2 concrete and steel bridges
147
Q

Flood frequency plot

A
  • of historical data
  • to estimate return period for given size flood
  • river discharge vs return period (yrs)
  • use for designing roads, bridges, buildings
148
Q

100-yr flod

A

1% probability of occurring in any year

149
Q

flood safety, before

A
  • build flood resistant
  • listen for warnings
  • if time permits, move valuables above ground level, turn off furnace, gas
  • if imminent, turn off power, plug sewer drains
150
Q

make your home flood resistant

A

seal ground-floor/basement windows, doors

  • install drains
  • install sump pump, one-way valves in drains
151
Q

flood safety, during

A
  • listen to radio

- do not cross flooded area

152
Q

flood safety, after

A
  • wear boots
  • beware of electrical shock
  • dispose of food/water exposed to flood (contaminated)
  • do not move back in until dried, disinfected
153
Q

Flood structural mitigation

A
  • contain waters: dams, levees, floodways

- increase river carrying capacity: deepen, widen channel, remove debris/ obstructions

154
Q

Flood non-structural mitigation

A
  • zoning, land-use policies
  • education and evacuation planning
  • improved flood forecasting (satellites, river gauges, etc)
155
Q

Red River

A
  • flows N
  • drains N/S Dakota, Minnesota, Manitoba
  • Slowly meanders
  • broad floodplain
  • frequently floods
156
Q

Red River flooding causes

A
  • geologically young (less than 9000yrs) – not carved deep
  • valley underlain by impermeable red clay
  • low riverbed slope (8cm/km)
  • prone to icejams (S->N flow)
157
Q

1950 Winnipeg flood

A
  • snowy winter
  • late thaw
  • dike collapse
  • flooding of 1600 km2
  • largest CAD evac., over 100,000 ppl, 1/3 of Winnipeg pop.
  • 51 day flood
  • 10,000 bldgs damaged
  • RR floodway built in response
158
Q

RR Floodway

A

48km long, 140m wide artificial flood-control waterway around Winnipeg

  • normally empty
  • in flood, gates open to divert water around city
  • built for 1-in-225 yr flood
  • typically required every 2-3 yrs
159
Q

1997 RR flood

A
  • ‘96 fall rainfall 4X normal
  • early cold, froze soil
  • record winter snow pack
  • spring blizzard
  • rapid thaw
  • N Dakota: 60,000 evacuated, 120,000 cattle drowned, $1B damage
  • Manitoba: saved by dike, diverted water at (peak) 1400m3/s, nearly overwhelmed dykes
160
Q

Alberta flood, 2013

A

$5B damages (costliest CAD disaster)

  • S and central AB
  • Bow, Elbow, Highwood, Red Deer, Sheep, :little Bow, S Sak. rivers
  • calgary directly hit
  • 2200 CAD forces deployed
161
Q

cause of 2013 AB flood

A
  • heavy spring rainfall
  • low-pressyre system blocked S of AB
  • resulting air from E pumped moist warm air across semi-arid slopes
  • heavy rains particularly over Calgary, >300mm
  • saturated ground, steep watershed, heavy snow load
  • rivers up to 10X normal flow rate
162
Q

2013 AB flood, impact

A
  • largest evacuation in cities history, 75,000 ppl
  • days before power restored
  • central business district off-limits for nearly a weak (very important business hum in CAD)
  • bonnybrook bridge collapse
  • 150 ppl stranded on rooftops in High River
163
Q

Boonybrook Bridge Collapse

A
  • under weight of CPR freight train
  • pilings scoured by floater, undermined strength
  • train was carrying hazardous petrochemicals
164
Q

what went well in AB flood

A
  • modern construction and codes
  • good forecasting and governance
  • social trust
  • low loss of life despite huge level of destruction
  • rapid rebuild
165
Q

snowpack on slopes can fail due to gravity as

A

creep
fall
slide
flow

166
Q

avalanche path

A
  • similar to landslide
  • A starting zone (steepest, 30-45º)
  • B Track, guided by topography (20-30º)
  • C Run-out zone (less than 20º)
167
Q

Avalanche types

A

Size 1 -5

  1. relatively harmless, 10tonnes, 10m, 1kpa
  2. could injure or kill, 100t, 100m, 10kpa
  3. damage buildings/vehicles, 1000tonnes, 1000m, 100kpa
  4. destroy large vehicles, forests, railways, 10,000tonnes, 2000m, 500kpa
  5. 100,000 tonnes, 3000m, 1000kpa
168
Q

snowpack

A
  • deposited by multiple storms
  • layers w/ diff. properties
  • powder and wet
  • denser near bottom, with age
  • hoar frost crystals can grow btw layers
169
Q

snowpack, powder

A
  • 95% void
  • does not pack
  • dry, not sticky
  • doesnt stick together
170
Q

snowpack, wet snow

A

water between ice

-packs well

171
Q

snowpack layer boundaries

A

planes of weakness

172
Q

loose powder avalanche

A
  • acts like flow
  • high speed (65-100km/hr)
  • light snow
  • buries victims
  • largely unharmed, but can smother, disorient
173
Q

slab avalanche

A
  • slab of heavy cohesive mass detaches at layer boundary
  • acts like translational slide evolving into flow
  • speed 30-65km/hr
  • death, destruction
  • most dangerous
174
Q

avalanche safety -before

A
  • consult avalanche bulletins

- carry avalanche kit

175
Q

avalanche safety - during, after

A
  • escape to side, can’t outrun
  • if caught, ditch backpack, skis, poles
  • use swimming motion to stay near surface
  • maintain air pocket in front of face
  • stay calm
176
Q

avalanche survival rate

A
  • 50% if buried 30min.

- 15% for 2hr burial

177
Q

Extraterrestrial impacts

A
  • asteroids
  • comets
  • fragments of asteroid and comets
178
Q

fragments of asteroids and comets

A
  • meteoroid
  • meteor
  • meteorite
179
Q

before impacting Earth

A

meteoroid

180
Q

most impacts

A
  • asteroid fragment

- meteoroid

181
Q

asteroid

A
  • stony, metallic body
  • orbiting sun in inner solar system
  • medium sized
  • smaller than a planet, larger than meteoroid
  • 1-1000km
  • sometimes called planetoid, minor planet
182
Q

comet

A
  • small (.1 - 40km diameter)
  • highly elliptical orbit
  • nuclei of rock, dust, water ice, frozen gases (CO, CO2, CH4, NH3)
183
Q

meteorite

A

after impact with Earth

184
Q

Asteroid ‘belt’

A
  • 1-2 million asteroids between MVEM (terrestrial) and JSUN (gas giants)
  • likely ‘failed planet’
185
Q

why would asteroid belt be a failed planet

A
  • Jupiter’s gravity prevented coalescence

- large gap btw MVEM and JSUN

186
Q

smaller asteroid orbits

A

3 small groups that intersect E/M orbit

  • Apollos group (>1000 asteroids)
  • Aten group
  • Amors group
187
Q

meteor

A

while passing through atmosphere

188
Q

Multiple impacts

A

2+ asteroids can be gravitationally bound

189
Q

asteroid/comet fragment before it impacts Earth

A

meteoroid

190
Q

Comets in inner SolarSystem SS

A
  • solar radiation vaporizes volatiles in nucleus = tail
  • tail points away from sun
  • tail up to 1 AU
191
Q

AU

A

astronomical unit

  • distance from sun to E
  • 150M km
192
Q

Meteorite types

A
  • stony

- Fe-rich

193
Q

Most meteoroids are

A

chondritic

-burn or break up in atmosphere)

194
Q

meteoroid influx

A
  • 100B meteoroids/day
  • add 100-1000t to E
  • number of impacts decrease w/ size
195
Q

angle of impact

A

important to whether it will burn up

196
Q

of 1mm diameter meteoroids

A

1/30seconds

197
Q

cosmic dust

A

less than 1mm diameter

-drifts down gently

198
Q

shooting star

A

ca. 1mm
- melt about 100km above E
- glow for about 1s

199
Q

meteorite influx

A
  • 1mm -100m
  • reach E surface
  • up to 3000º
  • slowed by atmos.
  • 320-640km/hr
200
Q

1m diameter meteoroids

A

1/yr

201
Q

impacts >350t

A

pass through atmos. largely unaffected

202
Q

Craters

A

simple or complex

203
Q

simple crater

A
  • smaller meteorite
  • raised rim
  • concave bottom
  • no uplift
204
Q

Complex crater

A
  • larger meteorite, asteroid, comets
  • melt/vaporize rock
  • central uplift from rebound
  • collapsed outer rim leaves crater 20X larger than impacting body
  • new mineral formation from high T/P
205
Q

Earth impact craters

A
  • erased by erosion, subduction, cont. collision, infilling of sed.
  • 164 known, 58 in NA
206
Q

why so many craters in NA

A

large landmass

207
Q

some Canadian impact craters

A
  • Manicouagan, Quebec, 75km
  • Lake Wanapitei, Ontario
  • Pingualuit crater, Quebec
208
Q

Tunguska event

A

1908, Siberia

  • massive fireball
  • heard 1000km away
  • not inhabited
  • reindeer killed
  • man 60km away burnt
  • people 480km away knocked off feet
  • 80M trees damaged
  • no impact crater
209
Q

what happened in Tunguska event

A
  • stony meteorite or comet frag.
  • 30-50m diameter
  • exploded at 8km elevation
  • blast equivalent to 10-15Mt of TNT , 1000X more powerful than atomic bomb
210
Q

KTB

A
  • 65MYa
  • 1cm clay layer between KT
  • K rocks have abundant fossils, T do not
211
Q

Chelyabinsk meteor

A

Russia, 2013

  • 20m near-E asteroid, miss
  • 19km/s
  • light brighter than sun
  • visible 100km away
  • exploded in air –> hot dust and gas cloud
  • blast yield 20X Hiroshima a-bomb
212
Q

why did Chelyabinsk explode

A

high V

shallow entrance angle

213
Q

KT extinction

A
  • 85% of species disappeared
  • dinos, marine reptiles, many plants
  • many severely reduced numbersL fish, plankton, molluscs
  • mammals (small), birds, suffered few extinctions
214
Q

KT asteroid evidence

A
  • Ir layer around world, 300X normal
  • clay quartz grains ‘shocked’
  • spherules
  • radioactive ratios
  • tsunami deposits in Yucatan peninsula
  • buried impact crater (Chicxulub)
215
Q

How Chicxulub was found

A
  • petroleum well encountered 90m thick zone shattered rock, shocked quartz, globules, dated 65Mya
  • radar topography indicates 180km ring (trough)
216
Q

likely effects of KT impact

A
  • M11 eq
  • 300m tsunami
  • worldwide fires
  • dust, soot clouds block sun for weeks-months
  • water vapour, CO2 in atmos. cause GH warming
  • high death rate for many except carrion feeders
217
Q

Impact hazards

A
  • rare
  • no confirmed fatalities
  • 1 documented injury, Lethbridge 1954
  • very small probability of catastrophic (KT size) and large (Tunguska size) impacts
  • NEOs monitored
218
Q

NEOs

A
  • near Earth objects

- could be deflected by NASA

219
Q

Space weather

A
  • suns behaviour changes (sunspots, solar winds, magnetic storm)
  • causes disturbances in E’s magnetic field - magnetic storm
220
Q

solar cycle

A
  • 11-yr change in suns activity (sunspots, flares, etc)

- causes effects in space, atmosphere, and E’s surface

221
Q

Magnetic storms

A
  • strong aurora borealis - indicate hazardous charged particles in atmos.
  • severe storm could disrupt power grids
222
Q

Carrington Event

A

1859

  • sunspots observed
  • southern aurorae observed far N on Australia
  • solar flares observed
  • flare associated w/ major coronal mass ejection (CME) that hit E w/i 18hrs
  • geomagnetic storm next day on E
223
Q

Carrington Event, geomagnetic storm

A
  • largest recorded
  • aurorae around the world, could read by them in US
  • telegraphs failed, shocked operators
224
Q

SWORM

A

Space Weather Operations, Research, and Mitigation

  • US task force against space weather
  • give 0.5 -2 day warning
225
Q

Most deadly/destructive weather hazard

A

Hurricane

226
Q

Hurricane effects

A
  • huge areas, up to 4000km2
  • high winds, up to 240km/hr
  • storm surges raising sea level, 6+m
  • heavy rains
227
Q

Tropical cyclone

A
  • powerful rotating low-P system
  • warm core
  • form between 5-20º of eq.
228
Q

tropical cyclone with 1+ minutes sustained winds > 119km/hr are:

A

Hurricanes in Atlantic
Typhoons in Pacific
Cyclones in Indian

229
Q

Deadliest worldwide disasters 1970-2011

A
  1. Cyclone, Bangladesh, 1970, 400,000d
  2. Eq., China, 1976, 255,000d
  3. Eq+tsunami, Indonesia, 2004, 245,000d
  4. Eq., Haiti, 2010, 230,000d
  5. Cyclone, Myanmar, 2008, 140,000
  6. Cyclone, Bangladesh, 1991, 140,000
230
Q

Costliest disasters worldwide, 1970-2010

A
  1. Hurricane Katrina, USA, 2005, $50,850 millions of 2010 US dollars
  2. Hurricane Andrew, USA, 1992, $25,170 MUS
  3. Terrorist attack, US, 2001, $23,409
  4. Eq, USA, 1994, $,849
  5. Hurricane Ike
  6. Hurricane Ivan
  7. Hurricane Rita
  8. Hurricane Wilman
  9. Hurricane Charley
231
Q

Canadian deadly Hurricanes, 1900-2011

A
  1. Galveston, Atl., 1900, 80-100d
  2. The August Gale, Atl., 1927, 56d
  3. Hazel, Atl., 1954, 81d
    Pacific only has 2 in top 15
232
Q

N Atlantic hurricanes

A
  • hurricane season June 1- Nov 30
  • peak mid-August- late October
  • storm diameter 200-1300km
  • lifespan 1-30 days
  • direction - W then N
  • surface winds counter-clockwise
233
Q

Hurricanes require

A
  • warm SST (>27ºC in upper 60m)
  • warm, humid, unstable air
  • weak upper level wind
  • coriolis
234
Q

forces balanced to produce cyclonic flow

A

-P gradient - force towards low P eye
-Coriolis - perpendicular to motion
-Centrifugal - radially outward
-Friction - opposes motion
NET motion - spiral in

235
Q

Hurricane formation stages

A
  1. Tropic disturbance
  2. Tropical depression
  3. tropical storm
  4. Hurricane
236
Q

Tropic disturbance

A

low P zone, draws in thdrstorms

  • weak winds, 36km/hr
  • not named
237
Q

Tropical depression

A
  • strengthening wind, 27-63km/hr
  • coriolis causes cyclonic wind flow about low P core
  • converging winds flow upwards near core, moisture condenses, releasing latent heat, intensified updraft
  • not named
  • identified by number
238
Q

cyclone direction in SH

A

clockwise

239
Q

Tropical storm

A

winds 64-118km/hr

-identified by name

240
Q

Hurricane

A

winds >119km/hr

  • now winds reach core, forms eye
  • identified by name
241
Q

Hurricane eye

A
  • generally circular, 30-65km
  • calm, clear, low P
  • surrounded by eyewall
242
Q

eyewall

A
  • cylindrical area of upward spiralling winds

- strongest wind of hurricane

243
Q

Hurricane decline

A

when cut off from water water E source

  • landfall
  • moving over cold water (Canada)
244
Q

Hurricane paths

A

generally, in NH:

  1. start at 10-20ºN
  2. trades winds push to west at low lats.
  3. coriolis forces push to right
  4. westerlies push to East at higher lats.
  5. path influenced by bermuda high
245
Q

why no hurricanes at 0-10ºN?

A

no coriolis!

246
Q

Bermuda high

A

high P zone over mid Atlantic

247
Q

Hurricane winds

A

add/subtract wind speed

  • Hurricane w/ internal wind speed 160km/hr moving NW and 30km/hr
  • 190km/hr wind speed on ground to the NE
  • 130km/hr ground speed to SW
248
Q

storm surge

A

rise in sea level due to:

  • strong onshore winds pileing up water
  • low atmos. P beneath eye carrying mound of water
  • very dangerous if coincide w/ high tide
249
Q

Maximum storm surge in NH

A
  • 15-30km to right of eye path

- strongest winds

250
Q

Cat5 storm surge

A

> 5.5m

251
Q

record storm surge

A

13m, Australia, 1899

252
Q

major cause of property damage in NA and death in low-lying countries like Bangladesh

A

storm surge

253
Q

Bangladesh storm surge

A

7/9 of most deadly weather events in 20th C

  • deltas 30cm above sea level
  • 35% of country less than 6m above sea
  • 5 cyclones/yr
  • increasing population
  • increasing sea level
254
Q

Hurricane scale

A

Saffir-Simpson Scale

Cat 1-5

255
Q

Hurricane Category 1

A

Minimal

  • winds damage trees
  • 119-154km/h wind
  • 1.2-1.5m storm surge
256
Q

Cat2 Hurricane

A

moderate

  • blow down trees
  • major damage to mobile homes
  • 155-178km/h wind
  • 1.8-2.4m SS
257
Q

Cat3 Hurricane

A

extensive

  • blow down large tress
  • small buildings destroyed
  • ca 200km/h wind
  • 2.7-3.7m SS
258
Q

Cat4 Hurricane

A 
Extreme
-signs blown down
-heavy damage to windows, doors, roofs
-flooding kms inland
-211-250km/hr wind
4-5.5 m SS
259
Q

Cat5 Hurricane

A

catastrophic
-severe damages, buildings overturned
->250km/hr wind
>5.5m SS

260
Q

Hurricane Camille

A

Florida, 1969

  • Cat5, >320km/hr wind, 7.3mSS
  • 256deaths
261
Q

Hurricane names

A

1953-1979 only female names

  • since 1979 WMO uses preselected list of alternating fm/m names, recycled every 6yrs
  • names of extreme storms retired (Katrina replaced by Katia, Juan replaced by Joaquin)
262
Q

Hurricane safety, before

A
  • listen to warnings
  • evacuate from coastal area
  • park in safe place, not under trees
  • take cover
  • close/shutter/ board windows
  • secure items (lawn furniture, bikes)
  • stock food/water, batteries
263
Q

Hurricane safety during

A
  • keep informed
  • stay in secure room w/o windows
  • use phone only for emergencies.
  • stay inside during passage of eye
264
Q

hurricane safety, after

A
  • inspect property
  • report downed lines
  • take photos of damage
265
Q

hurricane mitigation

A
  • Land-use planning: avoid pop. centres in low-lying coastal land
  • building codes: stronger codes for mobile homes, strengthen rook
266
Q

key requirements to prevent hazards from becoming disasters

A
  • good governance allows
  • affluence to afford
  • science to inform regulation
  • and respond
  • democracies
  • high trust societies
267
Q

2017 Atlantic hurricanes

A
  • hyper active season
  • 7 named storms, tied for 5th most active season
  • ACE + number major hurricanes highest since 2005
  • costliest year on record
  • 2nd yr on record w/ 2 Cat5’s making landfall
  • Irma strongest ever outside of GoMex and Caribbean
  • only yr that 3 hurricanes had ACE >40 (Irma, Jose, Maria)
268
Q

ACE

A

accumulated cyclone energy

269
Q

2017 Atl Hurricane cost

A

US$316.51B

-mostly all due to Harvey, Irma, Maria

270
Q

Katrina

A

2005, New Orleans

  • costliest natural disaster (pre-2012), $50+B
  • 6th strongest recorded
  • 1/5 deadliest storms in IS history
  • 1800d, 700missing
271
Q

2005 hurricane season

A

one of most active ever

  • most named storms (28)
  • most hurricanes (15)
  • most major hurricanes to hit US (4)
  • costliest US hurr (Katrina)
  • costliest Mexican hurr (Wilma)
272
Q

New Orleans and Katrina

A
  • 1.2M people
  • much of city below sea level, estuary, and Mississippi river
  • protected from lake and river by levees
273
Q

Katrina time line

A

Aug 25: hurricane status 2hr before reaching Florida, surprised, killed 14
Aug 26: 17% chance of hitting NO (by computer models) w/ 8.5m SS
Aug 28: reaches Cat5 over GoM (unusually warm waters 28-32º), NO begins evac.
Aug 29: landfall 55kmE of NO as Cat3, 195km/hr wind on Miss./Alabama coasts, 8m storm surge screeched levee in 53 places, flooding of 80% of NO

274
Q

Was Katrina foreseen

A

yes

  • years in advance
  • by reports, studies, journals, weather forecasts
275
Q

Katrina, rain

A
  • extremely heavy local rains as far north as CAD
  • up to 10cm rain in ON
  • flooding in ON, QB
  • 16” in FL 40cm
  • 15”, 28cm in LA
276
Q

New Orleans failures

A
  • levee failures forecast, nothing done
  • weather forecast good, evacuation delayed
  • failure of leadership at all levels
  • low trust, corruption
277
Q

how could Katrina have been worse

A
  • maintaining CAT4 or 5
  • speeding up, earlier landfall
  • earlier break of levee
  • faster flooding
278
Q

Hurricane Juan

A

2003, near Halifax

  • Cat2, 160km/hr at landfall
  • extensive wind damage to NS, PEI
  • 8killed
  • $300M damage
  • 2m SS
  • worst storm to hit Halifax in >100yr
279
Q

Hurricane Juan damage

A
  • 31% of homes in Halifax damaged
  • millions of trees damaged or downed
  • downed power lines
  • 300,000 w/o power
  • grounded boats
280
Q

Juan retirement

A

name Juan retired after its effects in Canada in 2004

-first time CAD requested a name be retired

281
Q

Hurricane Juan governance

A
  • well forecast, action taken at all levels
  • high trust society
  • ready to respond quickly after event
  • coherent response at all levels
  • not perfect, but good
282
Q

when did wildfire begin

A

appears in geo records after land plants evolve

  • Ordovician
  • 450Mya
283
Q

fire influences

A
  • vegetation distribution, structure
  • carbon cycle
  • climate
284
Q

Canadian forests

A
  • 10% of worlds forests
  • Boreal forests 60% of CAD surface area
  • BC dominated by temperate coniferous
  • ON, PQ, maritimes are temperate broadleaf
285
Q

boreal forest

A

mixed coniferous and deciduous trees

286
Q

Canadian wildfire

A
  • average 2.5million ha /yr

- huge inter annual variability

287
Q

1 ha

A

2.471 acres
10,000m2
100x100m

288
Q

fires, chemical reaction

A

-C-H bonds broken in plants, generating CO2 and H2O

C6H12O6 + 6O2 -> 6CO2 + 6H2O + energy heat

289
Q

fire triangle

A
  • 3 elements required for a forest fire to burn
  • heat, oxygen, fuel
  • if 1 side of triangle is broken fire will die
290
Q

stage of combustion

A
  1. Ignition
  2. Preheating
  3. Flaming combustion
  4. Glowing or smouldering combustion
291
Q

Combustion, Ignition

A
  • human or natural
  • cigaretes, campfires, power-lines, equipment
  • lightning
292
Q

Combustion, preheating

A

water is expelled from plants by nearby flames and heat

293
Q

Flaming combustion

A
  • flames present
  • charcoal can be formed in absence of sufficient O2
  • greatest E release of fire
294
Q

glowing combustion

A
  • late stage
  • slower combustion
  • blue flame
  • smoke but no flame
  • rarely self-sustained
295
Q

forest fire classification by what part of forest they are in

A
  1. Ground fire
  2. Surface fire
  3. crown fire
296
Q

ground fire

A

0ften bellow leaves

297
Q

surface fires

A

up to 1m high

298
Q

crown fire

A

tops of trees

299
Q

ladder fuels

A
  • tall grasses, small shrubs
  • enable ground fires to carry upward into tall trees and form major fires
  • multiple types of fire at once
300
Q

factors that control wildfire starts and spreads

A
  • climate, weather
  • chemical constituents
  • insects
  • topography
  • people
301
Q

climate and weather, fires

A
  • temperature
  • humidity
  • wind
  • lighting
  • soil moisture
  • rainfall
302
Q

chemical constituents, fires

A
  • some plants have high oil content - easy ignition
  • eg. eucalyptus
  • some species more/less resistant to beetle kill
  • monocultures spread fire more rapidly
303
Q

insects, fires

A

-species such as mountain pine beetle destroy forests = easily combustible dead wood

304
Q

Fort McMurray wildfire, 2016

A
  • first time >60,000ppl so remote evacuate for fire in NA
  • ignited May 1
  • burned 600,000ha
  • $3.6B in insured losses
  • > 2400 buildings destroyed
  • no deaths from blaze (at least one vehicle crash on evac.)
  • 33º weather hard for firefighting
  • humidity 7%, winds 45mph
  • controlled July 5
  • extinguished Aug. 2
305
Q

Why the fire in Fort Mc.

A
  • months ahead of typical fire season
  • low P center brought hot SW winds across FM
  • record daily highs of 33º
  • uncommon bad timing - light winter snow, no summer greening yet
306
Q

Fire suppression

A
  • remove 1 wall of the triangle
  • water to remove heat
  • fire retardant to block oxygen
  • bulldoze forest to remove fuel

2017/2018 (7 decks)

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