Between a pile of melting snow and the rainfall this week, the City of Mississauga is bracing for potential flooding.
“The winter we had this year, it was colder than last year, so the snow held more water,” said Ben Gallagher, the city’s manager of the office of emergency management.
“That water ends up in our waterways,” he said.
Mississauga is home to many bodies of water, including rivers, lakes, stormwater ponds and Lake Ontario, which increases flooding — especially this time of year.
Early spring brings a mix of rapid snowmelt, heavy rain and breaking ice. All of which can cause water to build up faster than the ground and the city’s drainage systems can handle.
“One of the main things we want to get across to residents is to avoid putting yourself in any dangerous situations in the first place, really avoid any activity near the waterways,” Gallagher said.
Lessons learned from 2024 flooding
The city has learned a lot of lessons from torrential rainfall nearly two years ago that caused massive flooding, road closures and power outages.
On July 16, 2024, and then, a month later, on Aug. 17 and 18, two record-breaking storms unleashed 280 millimetres of rain on Mississauga, trapping people on flooded roads, running over the edges of creeks, and soaking into buildings. The larger Greater Toronto and Hamilton Area was also affected.
Last year, city council approved an action plan to ensure Mississauga’s stormwater system can continue to manage intense rain, ensuring the city is prepared for climate change-fuelled storms by pouring money into storm-water infrastructure upgrades.
The action plan’s goals include implementing flood mitigation initiatives and hiring additional staff to monitor and maintain the stormwater system.
“One of the things we want residents to know is just what that risk of flooding is in their neighbourhood,” said Gallagher, encouraging residents to check flood maps on the Credit Valley Conservation Authority’s website.
The water levels are extremely high across the region’s watershed, according to Girish Sankar, the conservation authority’s technical director of engineering services.
“We had approximately 40 to 60 cm of snow, and one of the things we do is measure the water content in that snow,” he said.
“It was measured to be anywhere to be 50 to 100 millitres of water content in that snow.”
Sankar says while those numbers are higher than they were in 2025, the main concern is when the snow melts quickly, especially when its accompanied by rainfall and warmer temperatures.
He says that’s what happened this week when temperatures reached the mid-teens with 25 mm to 30mm of rainfall occurring at the same time.
“One of the things that the conservation authority does is work with our municipalities to disseminate the flood messages we have,” he said, adding there is an alert system available to the public.
Officials recommend residents sign up for those alerts, and take preventive steps to help reduce water damage to their homes by keeping gutters, downspouts and eavestroughs clear.