Severe thunderstorms hammered the GTA Sunday, flooding roadways and causing multiple injuries at one Whitby festival.

Environment Canada issued a severe thunderstorm warning for Toronto around 12:30 p.m.

The agency warned of slow-moving thunderstorms in the region, resulting in heavy rainfall amounting to between 60 and 80 mm.

Around 1:45 p.m. a storm rolled over the Whitby Ribfest, with lightning striking a food tent while attendees were inside.

The incident sent 17 people to hospital, including one child, with non-life threatening injuries.

The Don Valley Parkway southbound on-ramp at Bayview and Bloor was closed due to flooding.

In south Etobicoke, flooding caused traffic delays, as cars and TTC streetcars struggled through the water.

Water levels were also high under a bridge in Scarborough near Bellamy Road and Eglinton Avenue.

In Scarborough, fire crews reported responding to an increase in water-related calls.

Toronto Fire Capt. Mike Strapko said fire crews responded to numerous calls about basement floodings and elevator rescues.