Ottawa could see up to 40 cm of snow Wednesday, Thursday as ‘highly impactful’ storm hits the region

A snowplow clears a parking lot in Ottawa. (Andrew Adlington/CTV News Ottawa)

A “highly impactful winter storm” is taking aim at the City of Ottawa ahead of the Family Day long weekend, with 30 to 40 cm of snow expected in a 24-hour period.

“This is the biggest one of the winter,” Environment Canada senior climatologist David Phillips said Tuesday.

Environment Canada issued a Winter Storm Warning Tuesday afternoon, saying the storm will hit Wednesday evening and continue until Thursday afternoon.

“Snow, at times heavy, will begin Wednesday evening. Total amounts of up to 40 centimetres are likely. This winter storm will impact the Thursday morning commute. Snow will gradually taper off through Thursday afternoon,” the warning says.

Snowfall rates could be as high as 5 cm per hour.

People are being told to “avoid travel if possible.”

“Rapidly accumulating snow will make travel difficult. Road closures are possible. There may be a significant impact on rush hour traffic in urban areas. If you must travel, keep others informed of your schedule and destination and carry an emergency kit and mobile phone.”

OC Transpo says it will be sharing information on the storm preparations and schedule on Wednesday.

Environment Canada says Ottawa could see 30 to 40 centimetres of snow Wednesday night and Thursday, which would be the biggest snowstorm of the season. The largest snowfall of the winter of 2024-25 in Ottawa was Dec. 6-8, when 24 cm of snow fell.

The winter storm warning is also in effect for Cornwall, Prescott-Russell, Smiths Falls, Perth, Arnprior, Renfrew and the Ottawa Valley. A special weather statement is in effect for areas including Brockville, Kingston, Belleville and Toronto, calling for 15 cm of snow Wednesday into Thursday and a risk of freezing rain.

“It’s going to strengthen through the Mississippi Valley and come into Ontario,” Phillips told Newstalk 580 CFRA’s The Morning Rush with Bill Carroll.

“I think Ottawa is lucky, in the sense that it’s not tricky precipitation; it’s snow. In parts of southern Ontario, in places like Toronto and London, Windsor, it’s going to be a tricky mix – it could be rain, it could be freezing rain, it could be snow. I’d rather take the chance of a 20 plus centimetres of snow.”

Phillips says more snow is expected on Saturday.

“It’s kind of a parade of these storms coming from the United States,” Phillips said. “It’s just going to brighten things up. My gosh, you are the snowiest national capital in the world and this is just what you expect.”

Ottawa has received 123.9 cm of snow since December 1.

“This one is what I call an honest winter,” Phillips said. “It was a little slow to arrive but when it did, we got the white Christmas. The amount of snow so far in Ottawa has been a little down – it’s probably about 85 per cent of what you would get for this time. That’s because you haven’t had a lot of these weather systems coming from the United States.”

Phillips says he doesn’t see any “melting temperatures” for Ottawa over the next couple of weeks.

City of Ottawa preparing for the storm

City of Ottawa crews are preparing for the storm.

“Our planning process is making sure we have all of our equipment ready, our materials ready, making sure our staff are all ready to work for the night shift and day shift,” Bryden Denyes, area manager, special operations, tells CTV News Ottawa.

“Really, it’s just monitoring that storm.”

Denyes says the city will go through about 180,000 tons of salt during the storm.

Ottawa’s forecast

Environment Canada’s forecast calls for flurries today. Amount 2 cm. High -5 C.

Clear tonight. Low -21 C, with the wind chill making it feel like -28 overnight.

Sunshine to start on Wednesday, with increasing cloudiness late in the afternoon. High -10 C.

Snow will begin Wednesday night and continue into Thursday. The high Thursday will be -3 C.

Friday will see sunshine. High -5 C.

The outlook for Saturday calls for periods of snow.

The normal temperatures for this time of year are a high of -4 C and a low of -13 C.

With files from CTV News Ottawa’s Dave Charbonneau