Lambton OPP closed Hwy. 21 at Grand Bend Sunday evening after severe thunderstorms ripped through the area on the leading edge of a sharp cold front.

Police say the severe weather knocked down trees and hydro lines causing significant property damage and power outages. Hydro One was reporting nearly 4,200 area customers without service with estimated restoration after midnight. Police said there had been no reports of injuries but the highway had to be shutdown to allow emergency crews to clean up. Lambton Shores reported via twitter around 10pm that Hwy 21. between Main St. and Klondyke Rd. had been reopened in both directions.

OPP said the Grand Bend Legion on Municipal Dr. was available as an emergency shelter for anyone impacted by the storm.

Environment Canada issued a tornado warning just before 7pm saying forecasters were tracking a thunderstorm on radar that indicated a possible tornado between Kettle Point and Grand Bend. The warning was downgraded to a severe thunderstorm warning about 30 minutes later.

The national weather agency was expected to send investigators to the area Monday to determine if indeed a tornado had caused the damage.