Overview
- Environment and Climate Change Canada has begun using the Convective Alert Modernization system so forecasters can draw free-form polygon warning areas and send targeted tornado and severe thunderstorm alerts to mobile networks and the WeatherCAN app.
- Polygons let meteorologists define the specific area a storm is expected to affect, which prevents blanket warnings for large pre-set zones and reduces notifications for people outside a storm’s path.
- Canadian forecasters and emergency officials say the change should cut false or non-impact alerts and make warnings quicker and more actionable, which can improve people’s chances of protecting themselves and property.
- Radio and television will continue to use the legacy colour-coded zone system because broadcast regions are large, and third-party weather platforms must adapt so both systems will run in parallel during the transition.
- The polygon approach follows U.S. practice that began in 2007 and has been linked to fewer false alarms, and officials say the next steps are wider platform integration and monitoring how the new warnings affect public response.