Severe thunderstorms can also produce tornadoes.
A severe thunderstorm watch and warning is in effect for the region.
Environment Canada is tracking a line of severe thunderstorms that could produce very strong winds and up to nickel size hail.
Large hail can damage property and cause injury while strong wind gusts can toss loose objects, damage weak buildings, break branches off trees and overturn large vehicles.
Severe thunderstorms can also produce tornadoes.
Emergency Management Ontario recommends that you take cover immediately if threatening weather approaches.