Canada to Overhaul Tornado and Severe Thunderstorm Alerts With Smaller, More Precise Warning Zones

A major change is coming to severe weather alerts in Canada, with Environment and Climate Change Canada expected to begin issuing much smaller, storm-based warning areas for tornadoes and severe thunderstorms as early as Tuesday.

Instead of warning entire large geographic regions, the new system will more closely target communities located directly in a storm’s projected path. The change could reportedly reduce the number of mobile phones receiving alerts by around 70%, helping limit unnecessary warnings for people far from the threat.

However, television and FM radio alerts may continue to rely largely on broader legacy warning zones. This means someone could hear a tornado or severe thunderstorm warning on the radio for a storm more than 100 kilometres away while receiving no corresponding emergency alert on their phone.

Canadians are therefore advised not to automatically disregard weather warnings heard on television or radio. Checking the actual warning polygon and storm track can determine whether a location is in the threatened area.

The change represents a significant move toward more precise severe-weather warnings while highlighting differences that may remain between mobile alerts and traditional broadcast systems.