Blizzards, snow storms Flashcards
What are the Canadian Weather Service criteria for a blizzard warning?
- 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
What are the blizzard warning criteria for the Prairies, Northwest Territories, and Nunavut?
- 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
When are snowfall warnings issued?
When there is a predicted accumulation of greater than or equal to 10 cm in less than or equal to 12 hours
When are winter storm warnings issued?
Prediction for snowfall accumulations of greater than or equal to 25 cm in greater than or equal to 24 hours
When are freezing rain warnings issued?
When freezing rain of a duration of greater or equal to 2 hours is forecasted.
What meteorological factors restrict the blowing of snow?
- Old snow
- Wet snow
- Rain and freezing rain
- Warmer temperatures
What meteorological factors enhance the blowing of snow?
- Fresh snow
- Cold temperatures
- Strong winds (cold fronts)
- Recurring weather patterns
- Lack of trees
Dangers of blowing snow?
Reduces visibility to 10km or less at least once a day
