Conservation authorities across the Greater Toronto Area are warning of flooding due to mild temperatures and rain over the next 24 hours.

Environment Canada is calling for a high of 10 C in Toronto today with showers expected early this afternoon.

A special weather statement issued for Toronto and much of the GTA Thursday afternoon says that some areas could see thunderstorms and between 15 and 25 millimeters of rain by this evening.

The soggy conditions have prompted the Toronto and Region Conservation Authority (TRCA) and Credit Valley Conservation to issue warnings about possible flooding in parts of the GTA today and tomorrow morning.

“Toronto and Region Conservation advises Environment Canada has forecasted 10-20mm of rainfall beginning Thursday around noon and tapering off early Friday morning. There is also a slight chance of thunderstorms during Thursday evening which could bring an additional 10-30mm of rainfall over a short duration,” the TRCA wrote in an advisory issued Wednesday.

“In addition to the rain, temperatures are expected to remain above zero today until overnight Friday, resulting in additional runoff from melting snow. Many of TRCA’s rivers and streams have full ice cover. The rise in water levels from rainfall and snowmelt could result in a break-up of the ice.”

Ice jams and localized flooding near culverts and bridge piers are possible today, the TRCA said.

“All rivers within the GTA may experience higher flows and water levels, resulting in potential flooding and hazardous conditions,” the TRCA continued.

“Ponding may occur in low-lying areas. The combination of slippery and unstable banks could create hazardous conditions close to any river, stream or other water body. All shorelines, rivers and streams within the GTA should be considered hazardous.”

John Sinnige, a spokesperson for Credit Valley Conservation, said they are concerned about three ice jams in the Credit River in Mississauga, Caledon, and Georgetown.

"Those ice jams have been causing flooding and right now the big concern is that we have some rain coming and are those jams going to let go or are they going to cause flooding," he told CP24 Thursday.

Sinnige noted that last week, for the first time since the 1980s, crews in Halton had to use dynamite to blast apart an ice jam that was causing problems in Glen Williams, Ont.

Credit Valley Conservation is advising people to stay away from the Credit River until further notice.

"It is very dangerous. When this ice lets go, it is instantaneous," he said. "If you are near the river, especially pets and kids. They can get caught up in it."