Vehicles under water in Gibbons parking lot as London sees one of its wettest April days ever

The London region is drying off after a day-long rain event that dumped nearly a month's worth of precipitation on the city in roughly 24 hours, Environment Canada said.

The national weather agency says London's airport recorded roughly 62.5 mm of rainfall from Wednesday morning overnight into Thursday, making it one of the top five wettest April days on record.

Most other areas around the city saw between 50 to 60 mm of rain in the period, with some exceptions, said Steven Flisfeder, a meteorologist with Environment Canada.

"There was one report of 74 millimetres that came from Ilderton; that was a volunteer report," he said, adding that overnight thunderstorms helped push up precipitation figures in some localized areas.

The day began with a messy morning commute due to freezing rain and ice pellets, which turned into rain in the afternoon. Thunderstorms and heavy rain showers between midnight and 3 a.m. produced a bulk of the rainfall the region received, Flisfeder said.

For some Londoners, the headache continued Thursday as the heavy rain, falling on ground already saturated from snow melt and last weekend's rainfall, caused flooding in several areas.

In Gibbons Park, the nearby Thames River overflowed its banks, partially submerging several vehicles in the park's parking lot. The vehicles remained stranded Thursday afternoon, with water up to their door handles.

Elsewhere, Windermere Fields, located just north of the Thames at the southwest corner of Adelaide Street and Windermere Road, was also underwater as of Thursday afternoon.

In the city's west end, drivers were forced to avoid Proudfoot Lane for another day south of Oxford Street. The city closed the roadway late Wednesday afternoon due to flooding along Mud Creek.

Outside of the city, OPP said a 32-year-old Middlesex County resident was seriously hurt Thursday morning after the rural roadway beneath their vehicle gave way around 6 a.m.

"The roadway appeared to collapse underneath a vehicle as it travelled on McEwen Drive, resulting in the collision. Water levels were very high as significant storms with heavy rainfall passed through the area," police said in a statement.

"At the upper end of the watershed, up near Mitchell, Stratford, St Mary's and toward Tavistock and Woodstock, those areas have already peaked today," said Eleanor Heagy, communications and marketing coordinator at the Upper Thames River Conservation Authority (UTRCA).

"That water is slowly making its way down the Thames ... toward London. We're expecting the peak to work its way through London overnight tonight."

Heagy stressed people should avoid local watercourses for the time being, and stay out of areas experiencing flooding. "Don't go wading into any flooded areas or anything like that."

Water level metres operated by UTRCA show increases began late Wednesday and continued through Thursday.

At Fanshawe Dam, levels in the reservoir had risen more than 3.5 metres as of Thursday afternoon, with flows of more than 400 cubic metres per second recorded, up from 50 a day earlier. Just south of the dam, water levels had climbed by nearly three metres to 9.25.

UTRCA officials say they don't anticipate severe flooding, but note the Thames will likely peak in the city at levels higher than what was seen late last month.

Short-term forecasts show Londoners shouldn't put away their umbrellas and rain boots just yet. Rainfall is expected late Friday and through Saturday, according to Environment Canada.

The national weather service says periods of rain are expected late Friday into Saturday morning, bringing precipitation amounts of 10 to 15 mm and a risk of thunderstorms.

On Saturday, periods of rain will continue, with the afternoon high hitting 14 C, Environment Canada says. Another 5 to 10 mm is anticipated.