Flash flooding closes 402 in '1 in 100 year' rainfall west of Strathroy

Many residents in Warwick Township were reporting flooded basements Thursday

Environment Canada is calling a dump of rain Wednesday night in the Glencoe area, southwest of London, a one in 100 year event that's left homeowners with wet basements and drivers still stunned by the closure of a major highway.

The weather service said just over 135 mm of rain fell in a short period of time, with more rain in the forecast Thursday.

"We warn people when 50 mm of rain falls in 24 hour, so this is almost double that," said meteorologist Trudy Kidd.

FORECAST: Storm chances bubble up in Ontario Thursday after parts of the south flooded

Drivers travelling west of Strathroy around 6 p.m. Wednesday found themselves wheels-deep in water caused by the heavy rain and flooding in the area.

Emergency services were forced to closed the highway for more than 12 hours overnight with water flowing across the highway and over the median, between Nauvoo Road and Kerwood Road.

Police were also reporting numerous crashes due to the flooding on roads in Middlesex and Lambton counties. The town of Glencoe, in Warwick Township, was especially impacted, with residents reporting flooded basements.

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"I've never seen it in all my time, this much rain so quick in our community," said Todd Case, mayor of Warwick Township. "When you get five to six inches of rain in a very short period of time, there's no infrastructure that's developed in Canada that can handle that."

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Emergency responders have been working overnight to put up road blocks and to help where needed. Case said.

"All hands have been on deck over the past several hours to close numerous roads that are been washed out and re-directing traffic," he said.

CBC - 402 closure with flooding - Township of Warwick Fire & Rescue Department - Aug24

The Ontario Provincial Police closed the 402, between exit 44 and exit 52, for more than 12 hours starting Wednesday evening due to flash flooding. (Township of Warwick Fire & Rescue Department)

There were still closures Thursday morning, though OPP did reopen the 402 at 7 a.m. Warwick township issued an alert telling drivers to avoid the following streets:

  • Sexton Road between Zion Line and Egremont Rd

  • Bethel Road from Egremont Road to Birman Line

  • Warwick Village Road accessing the Warwick Conservation Area south London Line

  • Zion Line between Nauvoo Rd and London Line

  • Warwick Village Road between Birnam Line and Hickory Creek

  • Hickory Creek Line from Elarton to Forest Road

  • Kingscourt between Confederation Line and Egremont.

WATCH: Storms overwhelm Ontario highway with water, stranding vehicles

Thumbnail image courtesy: Township of Warwick Fire & Rescue Department

This article was originally published for CBC News.