Blizzards, snow storms

Question 1

What are the Canadian Weather Service criteria for a blizzard warning?

Answer 1

• Low temperatures
• Sustained 40km/hour winds
• Snow/blowing snow restricting visibility to equal or less than 0.4 km
• Lasts greater or equal to 4 hours south of the arctic treeline
• Lasts greater or equal to 6 hours north of the arctic tree line

Question 2

What are the blizzard warning criteria for the Prairies, Northwest Territories, and Nunavut?

Answer 2

• Temperatures less than 0°C
• Widespread reduction of visibility 400m or less in snow or blowing snow
• Sustained winds at least 40km/h
• Lasts 4 hours south of the northern treeline
• Lasts 6 hours north of northern treelines

Question 3

When are snowfall warnings issued?

Answer 3

When there is a predicted accumulation of greater than or equal to 10 cm in less than or equal to 12 hours

Question 4

When are winter storm warnings issued?

Answer 4

Prediction for snowfall accumulations of greater than or equal to 25 cm in greater than or equal to 24 hours

Question 5

When are freezing rain warnings issued?

Answer 5

When freezing rain of a duration of greater or equal to 2 hours is forecasted.

Question 6

What meteorological factors restrict the blowing of snow?

Answer 6

• Old snow
• Wet snow
• Rain and freezing rain
• Warmer temperatures

Question 7

What meteorological factors enhance the blowing of snow?

Answer 7

• Fresh snow
• Cold temperatures
• Strong winds (cold fronts)
• Recurring weather patterns
• Lack of trees

Question 8

Dangers of blowing snow?

Answer 8

Reduces visibility to 10km or less at least once a day