Environment Canada reports that “significant rainfall” is possible in Toronto and surrounding regions starting Monday night and lasting several hours.
The federal weather agency stated that rainy periods are expected to continue until Tuesday night with possible total rainfall amounts of 15-25 millimetres.
Environment Canada’s meteorologist Gerald Cheng said that while Monday evening is not expected to be a major problem, conditions are expected to worsen on Tuesday.
“As we enter the overnight, there are chances of showers and temperatures dropping to zero.” Cheng stated that freezing rain could occur in the GTA at this time.
“We still see the possibility of showers tonight into Tuesday morning. Then the bulk of the rain, which will arrive just before noon, will continue to the evening.”
Environment Canada states that frozen ground is less able to absorb rainwater.
According to the agency, light freezing rain is possible over portions of southwestern Ontario and Oakridges Moraine on Monday night.
Expected rise in river levels
According to Toronto and Region Conservation Authority, river levels will rise as a result. The weather system will further break down and move river ice as well as create new ice jams.
According to the TRCAs, river water levels as well as ice jam conditions and locations can change quickly.
The TRCA stated that “with the combination of increased rainfall on frozen ground and snow and ice melting, water levels and flows will be higher this week due to the incoming weather system.”
“All rivers and streams in the GTA should not be considered to be dangerous because of the weather conditions that can lead to higher water levels, fast flowing water, and slippery or unstable banks.
According to the TRCA, the current conditions favor the movement and breaking of river ice along watercourses. This could lead to flooding in low-lying areas.
Ice jams can occur anywhere in a river, but most often they occur near culverts, bridges and bends in the river. TRCA also stated that jamming may occur at river mouths if the harbour is partially frozen.
Police warn of unsafe ice in open water bodies
The Toronto Police Marine Unit reminds everyone to avoid natural ice surfaces on bodies of water, such as the HumberRiver and Don River Ice Fields.
The unit stated that ice is also growing along the shore of Lake Ontario, especially in the areas of Catherine Street and Old Mill Drive. It stated that pets and people who climb over these areas could slip through the ice.
“With milder weather and rain expected this week,” the unit stated.
The Marine Unit advises that open water, storm water management pondice and water in general, are unstable and never truly secure.
The unit stated that road salt could make its way into lakes and rivers as Spring runoff begins to occur. This will further increase the instability of the ice.
“Storm water drains also into retention ponds. Many of these ponds are located in our parks including High Park Grenadier Pond.”
This week, more cold temperatures are in store for the city
Cheng indicated that Tuesday’s temperatures will be “very mild”, but that people should not become used to them.
Cheng stated that right now, Cheng is looking at a Tuesday high of 10 C. This is unusually high considering the normal for this time period should be around one degree.
“We are heading into Wednesday with temperatures expected to plummet, as you can see from the forecast. The mild temperatures will not last. We are still in winter, so we can expect colder temperatures to return.
He added, “And we may be discussing accumulating snow again before the end of the week.”
