The Toronto and Region Conservation Authority has issued a high water safety bulletin as snow piles will continue to melt with balmy temperatures this week.
The warning was prompted by Tuesday's 14 C forecast and expected rain showers.
"The mix of rain and snowmelt will result in increased flows and water levels in all our rivers, streams and ponds, creating unsafe conditions," the agency posted on its website.
"Please be aware of the unsafe conditions and advise any children under your care of these dangers and supervise their activities."
Temperatures are expected to remain at about 7 C this week and climb to 10 C on Saturday.
Flood warnings have been issued across much of Ontario. One particular community near Innisfil, south of Barrie, was deluged with water. In Stayner, businesses were forced to close as the streets were flooded.
The Ministry of Natural Resources uses hundreds of remote sensors to monitor river and lake levels across the province, which gives officials 48 hours notice of a flood threat.
The province has added a website to help people monitor flood risks at ontario.ca/flooding.
Wind warning
Tuesday's conditions also caused Environment Canada to issue a wind warning for the GTA. Winds were expected to reach 90 km/h in some of the affected areas.
Strong gusts blew down a large light standard off the overpass on McCowan Road and fell onto the busy Highway 401 on Tuesday afternoon. The situation caused traffic delays for several hours as both eastbound and westbound lanes were closed intermittently.
Toronto police, meanwhile, are warning drivers that the melting snow mixed with oil on the roads can cause slippery conditions. Motorists are urged to slow down and avoid potholes and driving through large puddles.
With a report from CTV Toronto's Matet Nebres
