Hydro-metereological Hazards Flashcards

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1
Q

What are hydro-meteorological hazards?

A

Natural processes or phenomena of atmospheric, hydrological, or oceanographic nature that may cause economic, sociocultural, or environmental loss. Natural processes and cycles that maintain ecosystems.

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2
Q

2 Causes of HM hazards

A

Climate and weather

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3
Q

What is weather?

A

Atmospheric conditions over a short period.

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4
Q

High pressure system

A

Areas of fair, settled weather

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5
Q

Low pressure system

A

Atmosphere is relatively thin. Winds blow inward towards these areas. This causes air to rise, producing wind, clouds, and condensation (rain)

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6
Q

Isobars

A

Lines on a map which connect areas with the same air pressure

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7
Q

Climate def.

A

The average weather at a location over a long period of time. Classified by temperature and precipitation.

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8
Q

6 Climate zones of Australia

A

Equatorial
Tropical
Subtropical
Arid
Grasslands
Temperate

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9
Q

6 factors of weather

A

Humidity
Precipitation
Air pressure
Temperature
Wind
Cloud Cover

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10
Q

Def. relief/ orographic rainfall

A

Formed when air if forced to cool when it rises over relief features in the landscape such as hills or mountains. As it rises, it cools, condenses and becomes rain

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11
Q

Why does low pressure cause rain?

A

Air can rise and condense into cloud cover to bring rain

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12
Q

Why doesn’t high pressure cause rain

A

Air descends towards the ground, air cannot rise and cannot condense into cloud cover

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13
Q

Cold front

A

Colder air replacing the warmer. As cold front moves, moist unstable air is usually replaced by cold, dry, stable air.

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14
Q

Warm front

A

Boundary between warm and cool air
Warm air at the surface pushes the above cool air mass, making clouds and storms.
Replaces cool dry air with warm moist air

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15
Q

6 Factors causing variation in climate

A

Latitude
Distance from sea
Altitude
Topography
Broad patterns in the ocean and atmosphere (ENSO)

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16
Q

What is ENSO (El Nino Southern Oscillation)?

A

Variation in Pacific ocean’s temperatures, air pressure and trade winds
Each phase lasts between 1 and 3 years
Measured by differences in sea level air pressure.
Differences recorded on the Southern Oscillation Index (SOI)

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17
Q

3 phases of ENSO

A

La Nina
El Nino
Neutral

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18
Q

La Nina

A

Warm water pushed west towards Australia
Strengthening of trade winds and Walker circulation
More precipitation
Flood and cyclone

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19
Q

El Nino

A

Warm water pushed east towards South America
Walker circulation breaks down
Less precipitation
Drought, bushfire

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20
Q

Neutral phase of ENSO

A

Trae winds blow east to west
Warm water pushed west towards Australia
Less extreme weather

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21
Q

Def. climate change

A

Long-term changes in average temperatures and weather patterns.

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22
Q

Def. global warming

A

Gradual increase in the overall temperature of the Earth’s atmosphere generally due to the greenhouse effect as a result of natural or human activities

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23
Q

4 natural processes that impact climate change

A

Solar variations
Volcanoes
Milankovitch theory
Albedo

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24
Q

Greenhouse effect

A

Gases such as CO2 in the atmosphere trap heat from solar radiation, creating a warm and livable atmosphere. Natural process

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25
Q

Enhanced greenhouse effect

A

Caused by human activities e.g. burning fossil fuels, which releases excessive greenhouse gases into atmosphere e.g. CO2 which trap more heat than normal

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26
Q

Bushfire def.

A

Wildfire is the internationally recognised term for describing a fire burning out of control in grass, scrub, or forested areas.

27
Q

Bushfire danger ratings

A

Moderate, high, extreme, catastrophic

28
Q

3 Types of fire

A

Ground fire- underground fire involving peat, coal or tree-roots
Surface fire- low to high intensity fire burning surface litter, grass, shrub layers
Crown fire- High intensity, spreading rapidly through the crown of trees/ canopy especially with high winds

29
Q

Grassfires

A

Most common
Up to 25 km/hr (fast)
Flat Grassland or scrubland
Potential to destroy crops, livestock and buildings

30
Q

Forest fires

A

Forests and woodlands, mountainous areas that are less accessible. Steep terrain and dense forest can result in very rapid, intense fires which are extremely hazardous to homes, infrastructure and human life

31
Q

7 factors that affect bushfire behaviour

A

Fuel load
Wind speed
Fuel moisture
Ambient temperature
Relative humidity
Ignition source
Slope angle

32
Q

3 response to bushfires

A

Bushfire management
Extinguishing fires
Community preparedness

33
Q

Impacts of 2019-2020 Black Summer Bushfires

A

19 million hectares burnt
33 people died
3500 homes destroyed

34
Q

Causes of 2019-2020 Black Summer bushfire

A

Not enough rain
Winds and heat
Low humidity
Dry fuels

35
Q

Causes

A

Climate change
Arson
Land management

36
Q

Location of Black Saturday bushfires

A

Kilmore, Kinglake, Murrindini, Marysville, North-east of Melbourne

37
Q

Factors increasing bushfire rise in Black Saturday

A

2 months of hot, dry weather
3 days above 43 degrees
45.1 degrees
Extremely low humidity levels
North-westerly winds above 100km/h

38
Q

Impacts of Black Saturday

A

173 deaths
400 individual fires
2100 homes destroyed
7562 people displaced
$4.4 billion in insurance claims

39
Q

Drought def.

A

A severe shortage of water relative to the needs of people, plants and animals in an area

40
Q

Areas most likely to experience drought

A

Areas that receive 250-500mm annual rainfall
Semi-arid areas

41
Q

Impacts of Millennium drought in Coorong region

A

Decreasing agricultural productivity, especially dairy
Decreased biodiversity, especially birds
Increased water salinity and acidity
Loss of jobs and livelihoods
Farmers forced to pay $3000 a week for water

42
Q

Why is Ballarat’s water supply not guaranteed?

A

Location of town was not determined by water supply, but by gold.
Ballarat located at a high elevation, covering the upper reaches of 4 catchment basins.

43
Q

Will water stress in Ballarat increase? Why?

A

Yes
Population is increasing
Temperatures are increasing
Rainfall is decreasing

44
Q

Water stress responses

A

Water restrictions
Harvest stormwater
Water-sensitive urban design e.g. water tanks, catchments
Bore water holes

45
Q

4 types of drought

A

Meteorological drought
Hydrological drought
Agricultural drought
Socioeconomic drought

45
Q

How can the end of a drought be determined?

A

When there is enough water to meet the needs of all people and the environment

46
Q

MODIS & FIRMS

A

Moderate Resolution Imaging Spectroradiometer locates fires as hotspots via a satellite.
Collects data in the form of FIRMS (Fire information for Resource Management System) to be analysed

46
Q

4 types of GIS used to respond to bushfires

A

MODIS
FIRMS
DEA
ESRI

47
Q

Weaknesses of GIS in bushfire management

A

MODIS cannot detect fires smaller than 100 m2 unless conditions are perfect.
Satellite views can be obstructed by smoke, clouds or tree cover.
Doesn’t distinguish b/w different types of fires e.g. oil rig fires and volcanoes

48
Q

Strengths of GIS in bushfire management

A

Combines info from a variety of sources
Assists with damage assessments and the issuing of warnings
A range of data can be collected
Live feed of fire behaviour

49
Q

DEA

A

Digital Earth Australia Hotspots is an Australian bushfire monitoring system using satellites to track the location and movement of bushfires

50
Q

Def. flood

A

When water temporarily flows over land that is normally dry.

51
Q

2 types of floods

A

River flood- Caused by rivers exceeding bank full capacity
Coastal flood-Caused by low-lying areas being inundated by sea-water

52
Q

5 main processes of hydrological cycle

A

Evaporation
Transpiration
Condensation
Precipitation
Runoff

53
Q

Impacts of floods on people

A

Inundation/ loss of homes
Damage to infrastructure e.g. bridges
Destruction of agriculture
Injury and death

54
Q

Impacts of flood on environment

A

Cycles nutrients and replenishes aquifers
Germinates dormant seeds
Urban floods degrade water quality
Carry pesticides and pollutes waterways

55
Q

3 types of runoff and describe

A

Surface runoff- Fastest, flows over the surface, little friction
Through flow- medium flow, flows through pore spaces in soil and rock
Groundwater flow- Slowest, flows through saturated soil and bedrock

56
Q

Storm surge

A

Change in sea level caused by a storm. Large winds and waves push water inwards e.g. extreme winds, low pressure, heavy rains

57
Q

Factors influencing flood hazards

A

Location
Vegetation
Urbanization
Soil type
Topography
Income
Recent weather

58
Q

4 types of flood

A

Slow on-set floods-Ample warning to prepare, lasts several weeks to months
Rapid on-set floods- sudden large amounts of rainfall, one to two days
Coastal floods- caused by strong winds from tropical cyclones, storms, and tsunamis. Sea water inundates low-lying coastal floods
Flash floods- short, intense rainfalls, that affect isolated locations on a small scale, lack of warning and predictability causes death and injury

59
Q

Tropical storm

A

Winds exceed 63 km/hr

60
Q

Tropical storm names depending on location

A

North atlantic/ pacific= hurricane
North-west pacific= typhoon
South pacific and Indian= tropical cyclone

61
Q

2 conditions required for a tropical storm

A

Large, warm, still ocean area (above 26.5 c)
Low altitude winds (blowing different directions)