Lecture 15 Flashcards

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1
Q

Blizzard

A

Visibility < 400 m because of wind speeds of >40 km/h
and blowing or falling snow for 4 hours or more
Interaction between upper-level low pressure trough and surface low pressure
Different locations have different classifications

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2
Q

Sleet

A

Rain/snow melts, then refreezes near ground level, forms mostly <1 mm diameter ice particles

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3
Q

Freezing rain

A

Supercooled rain freezes when it contacts ground

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4
Q

How do blizzards form?

A

Interaction between upper-level low pressure trough and surface low pressure

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5
Q

Fronts

A

Boundary between two air masses of different density and temperature

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6
Q

Advancing cold front

A

Forces warm air up

Creates clouds and heavy precipitation

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7
Q

Advancing warm frount

A

Forces warm air over cooler air

Creates clouds and precipitation

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8
Q

Special weather statements

A

Least urgent type of alert

To let you know conditions are unusual and could cause concern

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9
Q

Advisories

A

Issues for specific weather events that are less severe but could still significantly effect Canadians

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10
Q

Watches

A

Alert you about weather conditions where there is potential for a significant storm or severe weather to occur
Can be upgraded as more information becomes known

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11
Q

Warnings

A

Urgent messages that severe weather is either occurring or will occur
Updated regularly

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12
Q

Snowfall warning

A

A snowfall accumulation of 15 cm or more is expected in 12 hours or less

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13
Q

Freezing Rain Warning

A

Freezing rain is expected to last for 2 hours or more, or if slippery or hazardous walking or driving conditions due to freezing precipitation is expected

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14
Q

Frost warning

A

When the air temperature is expected to fall below or near freezing ( 0°C ) during growing season

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15
Q

Winter storm warning

A

When severe and potentially dangerous winter weather conditions are expected, including:
A major snowfall (25 cm or more within a 24 hour period); and
A significant snowfall (snowfall warning criteria amounts) combined with other cold weather precipitation types such as: freezing rain, strong winds, blowing snow and/or extreme cold

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16
Q

Alberta clipper

A

a fast-moving winter weather system originating in the lee of the Canadian Rockies that typically brings snow, high winds, and cold temperatures across the prairies

17
Q

Maritimes Nor’easter

A

Warm moist air picked up in the tropics moves north up the coast with Gulf Stream; origin often Cape Hatteras, NC
A mass of polar air from Eastern Canada and the North Atlantic moves south
Somewhere in the vicinity of Cape Cod the warm air hits the cold air.
The warm air moves up and over the cold layer.
Low pressure develops, counterclockwise cyclone means that coastal areas get northeasterly winds as the storm approaches

18
Q

Colorado low

A

Low-pressure area that forms in southeastern Colorado or northeastern New Mexico, typically in the winter. After forming, the system moves across the Great Plains

19
Q

Direct effects of blizzards

A

Frost bite, hypothermia (death)

Heart attacks during shovelling

20
Q

Indirect effects of blizzards

A

Loss of electricity
Auto accidents
# of blizzards deaths = or greater than tornado deaths in Canada and US

21
Q

Where are blizzards most common in Canada?

A

Southern prairies, Atlantic Canada, eastern Arctic

22
Q

Where are blizzards rare in Canada?

A

Wester NWT, BC and Yukon

23
Q

How may lives do winter storms and excessive cold claim every year in Canada?

A

100

More than combined toll from hurricanes, tornadoes, flood, extreme heat and lightning

24
Q

White Juan

A

Halifax, Yarmouth, Charlottetown
1m in 24h
Province wide states of emergency for 4 days
Nightly curfew for 3 days
>5 million in unbudgeted snow removal and wire repair

25
Q

1998 Quebec Ice Storm

A
January 
Quebec, NB, Ontario, NFLD
80 hours of freezing rain, some sleet
>25 deaths
$7 Bil, US
550, 000 without power
130 major transmission towers
30, 000 utility poles
120, 000 km of power lines and telephone cables
26
Q

Mitigation (6)

A

1) Better forecasts (not 12 hrs, but 24 hrs)
2) City planning for snow removal from sidewalks
3) Remind seniors at risk of heart failure
4) Dress appropriately
5) Remove trees near electrical wires
6) Consider underground infrastructure