Heavy rain in store for Toronto with possible localized flooding

Toronto remains under a special weather statement with heavy rain in the forecast that Environment Canada says could lead to localized flooding.

The federal weather agency says 15 to 25 millimetres of rain could fall, beginning Tuesday night into Wednesday.

Environment Canada said the mix of heavy rain, mild temperatures and melting snow could result in flooding in low lying areas and water pooling on roads.

All of the Greater Toronto Area, along with most of southern and eastern Ontario, remained on Tuesday night under a special weather statement and a flood watch as a result.

Thunderstorms are possible Wednesday afternoon and some areas may see even more rain by the time the system has moved through, Environment Canada said.

"The frozen ground has a reduced ability to absorb this rainfall," the federal weather agency said. 

Daytime temperatures are expected to climb into the mid and high single digits Tuesday and Wednesday, and then remain above zero throughout the rest of the week.

Ontario issues provincial flood watch

Ontario also issued a provincial flood watch ahead of the heavy rain. The provincial flood watch across central and southern Ontario says enhanced runoff, elevated water levels and low-lying floods are possible.

The snowpack is at a depth of up to 100 centimetres around Ontario's cottage country and Bruce Peninsula, holding the equivalent of roughly 150 to 250 millimetres in some areas.

Snowmelt will combine with what Environment Canada says could be roughly 15 to 25 millimetres of rain Tuesday night through Wednesday across southern and eastern Ontario.

Residents urged to stay off any ice on bodies of water

Toronto police also issued a news release on Tuesday, asking people to stay off any ice formed on bodies of water because warming temperatures and runoff road salt are making them unsafe.

"It is crucial that the public avoid going onto the ice formed on Lake Ontario or other bodies of water in the GTA. Remember, all ice is unsafe, especially at this time of year," the news release read.

In a post on X, formerly Twitter, on Tuesday, the Ontario Provincial Police's Highway Safety Division urged people to be aware of potential standing water or flooding on roads.

The Toronto and Region Conservation Authority (TRCA) issued a flood outlook that will be in effect until the end of Friday. 

"Over the next three days, forecasted precipitation combined with warmer temperatures, frozen ground conditions and melting snow and ice will result in increased runoff into rivers systems and rapidly changing water levels," the TRCA says.

"The combination of slippery and unstable banks, and rising water levels could create hazardous conditions near rivers or other water bodies."

The TRCA says the weather conditions could increase the risk of river ice breaking up, moving and forming ice jams at bridges, culverts, bends in the river, and that in turn may cause localized flooding in low lying areas next to rivers and in areas where there is poor drainage.

According to the TRCA, ice jams can be difficult to predict, but it says it is concerned about the Humber River, Don River and Duffins Creek watersheds.

"All shorelines, rivers and streams within the GTA should be considered dangerous with higher flows, potential ice jams, and rapidly changing water levels," the TRCA says.