Thunderstorms: Information & Facts

Thunderstorms can move very quickly and can cause severe damage and prolonged power outages. They often include high winds, lightning, heavy rain, hail, and even tornadoes. 
 
There are two types of alerts to listen for when a thunderstorm is forming in your area:

• Severe thunderstorm watch: Favourable conditions for severe thunderstorms with large hail, heavy rain, intense lightning or damaging winds.
• Severe thunderstorm warning:  Developed storm is producing some or all of watch conditions. Tornadoes may also be produced in severe thunderstorm environment.

Preparing for Thunderstorms: Before, During & After 
 

Thunderstorm Basics

Thunderstorms usually last less than an hour, but they sometimes roll in as a series of storms, which can last hours. As air becomes charged with electricity during a storm, this creates lightning bolts, which travel at 40,000 kilometres per second. 

High winds can blow branches and other debris into busy roads or knock large objects off high balconies and buildings. Heavy rains can cause poor visibility and flash flooding, creating hazardous driving conditions. 

Thunderstorms occur most often in the spring and summer, because they develop in environments with plenty of moisture and warm air. 

Learn how to keep you and your family safe during a thunderstorm. 

Check out Environment Canada’s Public Weather Alerts site for updated weather warnings.

Stay informed on thunderstorm warnings through local radio or television stations -- keep a battery powered or wind-up radio in your home to stay up-to-date during power outages.