Heavy rainfall has renewed flood concerns in the city, prompting a number of road closures and transit delays on the cusp of rush hour.

The Bayview Extension has been closed just south of River Street due to flooding, as has the intersection of Waverly Road and Kewbeach Avenue in the Beaches. The city also closed Bayview Avenue between King Street and River Street.

A portion of Lake Shore Boulevard was closed for several hours between British Columbia Road and New Brunswick Way because of flood conditions. All lanes reopened shortly before 4 p.m.

Meanwhile, Metrolinx spokesperson Anne Marie Aikins says “high water level alarms” have gone off on the Richmond Hill corridor. The alarms act as a warning for the transit agency about unsafe travel conditions on GO train tracks. It’s the first time the flood alarms have gone off since being installed earlier this month, she said.

"We did have a high level water alarm go off to tell us it’s getting close but we visually inspected the corridor and we’re confident that it’s safe to run trains for now,” Aikens told CP24. “The rainfall has steadied but we’re going to monitor very, very closely and if we have any concerns we’re going to have to close the corridor and reroute those trains."

Aikins told CP24 that bus routes have also been impacted by the rains as drivers have been instructed to slow down on slick roads.

She urges GO riders to keep double check their route schedule for delays and cancellations. 

Continuous rainfall wreaks havoc on waterfront

Toronto and much of the GTA has been doused with rainfall amounts of 10 to 20 millimetres since Wednesday night and an additional 20 to 30 millimetres is possible as it dwindles tonight.

As of 5 p.m., a total of 34.8 millimetres of rain was recorded at Pearson Airport which topples a 64-year-old record.

So far, Toronto Island has seen 54.4 millimetres of rain.

A special weather statement previously issued for Toronto, Hamilton and parts of the GTA was called off at around 3:30 p.m. but city officials say they’re continuing to monitor waterfront areas.

City officials are working with the Toronto and Region Conservation Area (TRCA) to determine whether it’s necessary to close the Don Valley Parkway due to pooling on the roadway.

“We’re monitoring it closely,” City of Toronto spokesperson Wynna Brown told CP24. “There’s some indication the rain will peter off. We’re hoping that’s the case.”

The TRCA issued a flood watch earlier Thursday warning of rainfall amounts that could increase the already high lake levels.

“There may be possible flooding along the shoreline, creating potentially hazardous conditions around water and the shoreline,” the TRCA said in a statement. “The combination of slippery and unstable banks and cold water temperatures could create hazardous conditions close to any river, stream or other water bodies.”

The conservation authority urged residents avoid waterways, low-lying areas and underpasses.

People are also being advised to keep children and pets away from waterways.

Flooding hits Beaches-area hard

Today's non-stop rainfall has caused localized flooding in parts of the Beaches.

Residents on Kippendavie Avenue, near Queen Street East and Woodbine Avenue, say they've experienced flooding like this in the past and blame nearby storm drains.

"It's only been this bad as of today but water has been rushing down here for several weeks," Beaches resident Robbie Hanneesson. "Our back lane has been flooded -- to the point where water is going into my boots -- three times this week now. It's been really crazy."

City officials monitoring situation on Toronto Island

Earlier this month, the city restricted access to Toronto Island to residents-only after two weeks of consistent rainfall caused Lake Ontario to swell to dangerous levels.

Though an emergency evacuation of the island’s 700 residents was never deemed necessary, ferry service was suspended and businesses shuttered.

More than 20,000 sandbags have been placed along the shorelines to mitigate the rising waters.

Brown said crews are still stationed on the island and are continuing to tackle ongoing flood concerns.  

"They’re monitoring the conditions very closely. We do know that lake levels are very high this year so we’re keeping a close eye over there. We do know that about 40 per cent of the land mass is flooded there," Brown said Thursday.

"We’re communicating very closely with island residents to assist them where they may need the help. We’re keeping an eye on vulnerable residents over there as well."