2.4.1 Thresholds for Blowing Snow and Blizzard Conditions

Thresholds
  Drifting Snow* Blowing Snow** Blizzard
Meteorological Service of Canada (MSC) Winds: < 35 km/h (19 kt) Winds: 35-39 km/h (19-21 kt) Winds: >= 40 km/h (22 kt)
Visibility: < 1 km
Temps: <= -10°C
MSC Arctic Weather Centre     Winds: > 40 km/h (22 kt)
Visibility: < 1 km
Temps: <= 0°C or less
Duration: >= 6 hours
MSC Prairie Storm Centre     Winds: > 40 km/h (22 kt) 
Visibility: < 1 km
Temps: <= -25°C or less windchill
Duration: >= 4 hours
U.S. National Weather Service not defined not defined Winds: > 56 km/h (30 kt)
Visibility: < 0.4 km
Temps: not defined
Duration: >= 3 hours

*Drifting snow - snow on the move at a height less than 2 m.

**Blowing snow - horizontal visibility is restricted to 10 km or less because snow particles are raised by the wind to a height of > 2 m