Snow and blowing snow Tuesday evening resulted in whiteout conditions and forced the closure of many highways in southern Manitoba. However, there were no official weather warnings issued by Environment Canada, which left people scratching their heads.
Natalie Hasell with Environment Canada explains that there are a few different warnings or statements that can be issued during a winter storm. One of those is a Blowing Snow Advisory, which is only issued when Environment Canada believes that blowing snow caused by winds of at least 30 kilometres per hour will reduce visibility to 800 metres or less for at least three hours.
There is also a Blizzard Warning, which is issued when winds of at least 40 kilometres per hour are expected to reduce visibility to 400 metres or less for at least four hours.
"The issue with yesterday's event is that it was not expected to last three or four hours," explains Hasell.
She notes the snow and blowing snow were both mentioned in the forecast all day and says hopefully people understood that blowing snow also meant reduced visibility.
"We weren't expecting it to last for an extended period of time, which would have been necessary for these additional alerting messages to be sent out," adds Hasell.
She notes yes, there was blowing snow and yes, visibility was reduced to the point that some highways were closed, but with respect to how Environment Canada's system works, the conditions did not meet warning criteria.
Hasell says Environment Canada could also have issued a Special Weather Statement on Tuesday. However, she notes the Statement would only have mentioned the blowing snow, and since that was already stated in the public forecast, there was no reason to repeat this.
Environment Canada also has a Winter Storm Warning, but Hasell says this is for blizzard conditions and major snowfall. A Winter Storm Warning is issued when at least 25 centimetres of snow is expected in a 24-hour period or at least 10 centimetres in a 12-hour period, combined with other events such as freezing rain, strong winds or extreme cold.
"We were not expecting large amounts of snow yesterday," says Hasell. "So, we were nowhere near the criteria for Winter Storm."
Hasell says it was sort of the perfect storm on Tuesday. The light snow started falling late in the afternoon, right when it got extremely windy and just as motorists were driving home for work, heading out to the Winnipeg Jets game or going on a Valentine's date.
"It was probably the worst time that we could have something like this happen," she adds.
Meanwhile, Hasell says Environment Canada certainly welcomes weather tips from the public on stormy days like Tuesday. She notes input from Manitobans, especially those living outside of Winnipeg can help forecasters determine whether warnings should be issued. Tips can be called at 1-800-239-0484 or emailed to firstname.lastname@example.org or email@example.com. She suggests using #mbstorm when posting on Twitter.
Hasell also points out that Environment Canada is not responsible for closing highways in Manitoba.