Residents and businesses continue to clean up after violent thunderstorms rolled across the GTA overnight.
Deafening thunder and blinding flashes of lightning shook the region as torrential downpours dumped about 50 millimetres of rain in about an hour last night.
Strong winds of up to 100 kilometres per hour ripped out trees and tore down power lines, leaving thousands without power.
About 21,000 Hydro One customers were left without power, with the largest outages affecting Barrie, Owen Sound and Newmarket.
In the GTA, officials say Etobicoke, North York and Scarborough were the hardest hit.
Power was also knocked out to Pearson International Airport at about 9 p.m., causing several flights to be delayed or cancelled.
The weather forced promoters to cancel Sunday night's scheduled concert by Nickelback at Toronto's Molson Amphitheatre.
A thunderstorm watch was issued for the GTA on Monday afternoon, but it has now ended.
With files from The Canadian Press.
