Why Thunder Bay's 3-day spring storm is normal and needed with fire season near
While the snowstorm that hit Thunder Bay, Ont., this week may have been a shock after such a mild winter, experts said it's within the normal expected weather for March — and could be good news for wildfire season.
Thunder Bay can expect another five to 10 centimetres of snowfall Tuesday, but it will taper off overnight, said Trudy Kidd, a warning preparedness meteorologist at Environment and Climate Change Canada.
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The snowfall is expected to continue until sometime Thursday, she said, but the heaviest snowfall is likely over.
"It can definitely feel unusual, but it's certainly not unusual to see a snowstorm in March," said Kidd. "We get a lot of moisture coming from the Gulf of Mexico. It mixes with that cold, Arctic air from Northern Canada and it can really create these messy winter storms."
A woman crosses the street Monday during a burst of heavy snowfall. It's expected to continue snowing for the next few days. (Marc Doucette/CBC)
This particular storm is caused by a Colorado low, said Kidd, which is when low atmospheric pressure forms above the Rocky Mountains. The pressure systems are steered by air currents and can eventually impact weather far away from where they originated.
"It's quite common for Colorado lows to end up somewhere in northern Ontario," said Kidd.
This particular Colorado low that's hit this week collected moisture from the Gulf of Mexico and is dumping it over northern Ontario in the form of snow and rain, said Graham Saunders, a climate and weather professor at Lakehead University.
"Usually these Colorado lows will be fairly brief and duration especially in the in Thunder Bay-area. But this time it's it's lasting for days. It's stalled or very slow-moving over Minnesota and now over Lake Superior," said Saunders.
Multiple factors go into how fast a pressure system moves, said Saunders, so it's hard to say exactly why this storm is more drawn out than others.
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But this storm was desperately needed. The region's conservation authority has warned of drought conditions already this winter.
"We've had a moisture deficit for the last 12 months or more. So it's very dry and and this snowfall will remedy it in part," Saunders said. "We'll have a bit of a reprieve from spring forest fires."
"We're going to have a normal snow amount in March just because of this storm," said Saunders.
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Thumbnail courtesy of Marc Doucette/CBC.
The story was originally written by Michelle Allan and published for CBC News.
