'Wintermission:' Warm air, rain to arrive in Ontario raising the risk of potential flooding
Friday, January 10, 2014, 7:25 PM -
Much of Ontario will climb out of the deep freeze this weekend, with some places forecast to see daytime highs above 5°C.
"A deepening low pressure system will approach southern Ontario this evening and move north of the regions Saturday," said Environment Canada in a special weather statement early Friday. "Several weather types will occur before rain spreads across the region."
Light snow picked up across southern Ontario early Friday, resulting in slick and slow conditions for the morning commute.
Several crashes were reported along major highways through the morning with reports of drivers pulling off to the shoulders as they were "too tired and stressed" to continue driving.
Fog patches moved into the area as early as Friday afternoon. Freezing drizzle is also possible in some places, while the precipitation forecast to start with snow in the northeast.
"Late this evening the rain will move over southwestern Ontario and march eastward," EC adds.
Between 10 and 25 mm of rain are expected for most areas before tapering Saturday afternoon.
"Across eastern Ontario, freezing rain is likely overnight and during the early morning hours Saturday," EC says.
Environment Canada issued a freezing rain warning for parts of eastern Ontario and southern Quebec with two to six hours possible over these regions.
The estimated ice accumulation on surfaces is 2-5 mm. As a result, motorists are urged to adjust travel plans accordingly and prepare for local power outages as well.
"The freezing rain will change to rain across eastern Ontario Saturday morning and the rain may persist until Saturday evening," EC says.
NEXT PAGE: JANUARY THAW RAISES FLOOD CONCERNS
After starting as snow for northeastern Ontario, the precipitation is then expected to transition to rain for most areas south of a line from Montreal River to Kirkland Lake by Saturday afternoon.
"During this transition, there is a risk of freezing rain," says EC.
Areas northwest of the system are expected to see all snow with amounts of 10-15 cm possible through Sunday.
The heaviest snow is expected to fall over the Wawa to Timmins corridor.
Warmer air will accompany the rain, with many places seeing daytime highs rise well above the freezing mark Saturday.
"Much of southern Ontario will see a true January thaw with highs of 5-10°C forecast on Saturday," says Weather Network meteorologist Doug Gillham.
That's great news for those looking for a "Wintermission," but it has water conservation authorities on high alert.
"With the warm temperatures and the forecasted rainfall there is the potential for melting a portion of existing snow pack and ice cover on our creeks which will result in higher flows in all of our streams and creeks, resulting in dangerous flow conditions," said the Central Lake Ontario Conservation in a statement Thursday.
Officials say watercourses will be flowing higher than normal causing local streams and creeks to become dangerous. Melting ice may also result in hazardous conditions.
Residents are being asked to stay away from all watercourses and structures such as bridges, culverts and dams.
"Elevated water levels, fast flowing water and slippery conditions along stream banks continue to make these locations extremely dangerous," said the CLOC.
Ponding and flooding are also a concern with the warming temperatures and incoming rain. Toronto city officials say they have crews out with bobcats and front-end loaders trying to open clogged catch basins.
The recent heavy snow across parts of the province combined with the warm-up and rain expected this weekend is raising concerns about possible roof collapses as well.
Officials say the pressure of the snow can be too much for certain buildings and homes to handle and recommend hiring professionals to safely clear the snow.
HOW LONG WILL THE MILD TEMPS LAST?
"We'll continue to see mild conditions for the region on Sunday and Monday, but we'll then step back into a more typical January pattern for the rest of the week (typical rather than extreme temperatures swings) with the potential for a return to well below seasonal by next weekend and/or beyond," says Gillham.
The normal daytime high for this time of year is around -2°C.