WINNIPEG — Blowing snow created blizzard conditions for Winnipeg and parts of southeastern Manitoba Thursday morning. It’s a prime example of what a blizzard truly is. It’s not a snow event, it’s all about visibility.
First, this was expected. Light snow with very strong winds were expected Wednesday night into Thursday. A blowing snow advisory was issued across the southern prairies ahead of this. Snow totals were expected to be minimal with wind gusts up to 70 km/h. Thursday morning near 8:30 am the blowing snow advisory was changed to a blizzard warning by Environment Canada.
RAW: High winds, frigid temperatures hit Manitoba Thursday
The criteria for a blowing snow advisory is issued when visibility is expected to be less than 800 metres for a minimum of three hours. A blizzard warning is issued when winds are expected to be 40 km/h or greater causing widespread reductions in visibility to 400 metres or less, due to blowing snow, or blowing snow with a combination with falling snow for at least four hours.
In terms of Thursday’s blizzard, when it was clear the visibility would be be reduced beyond the original expectations, the blowing snow advisory was changed to a blizzard warning.
So how much snow fell that caused a near whiteout? Next to nothing.
It’s unlikely there will be any official snowfall amounts recorded for this snow event as the winds were so strong. There’s no way to tell what was new and what was old snow. Leading up to this weather event, most models were predicting around one cm falling in Winnipeg. If you were to say three cm fell, that would likely be at the high end of new snow. By far, the majority of the snow blowing around was left over from the last time it snowed in southern Manitoba, which was Jan. 9.
With very little new snow but very strong winds, Winnipeg and southeastern Manitoba got a good look at what really makes a blizzard. It’s not the new snow that counts, it’s all about the visibility.