Environment Canada launches targeted polygon alert system for severe weather

Environment Canada is rolling out a new extreme weather alert system on Tuesday that lets forecasters draw polygons around only the areas expected to be hit, rather than blanket-warning entire regions with colour-coded alerts.

The shift addresses what meteorologists call "alert fatigue" — the tendency of people to ignore warnings when they're repeatedly told they're in danger but the threat misses them. "When they do see a threat that it's likely to impact them, there is someone behind the scenes that is checking closely on these storms and they want you to do what you need to protect yourself, others and your property from harm," said Giselle Dookhie, an emergency preparedness meteorologist with Environment Canada.

The U.S. adopted polygon-based forecasting 16 years ago. Global News meteorologist Anthony Farnell said the system has produced big improvements south of the border. "The earlier you can get those warnings out to the people that will be impacted, the more likely you are to save property and then possibly save lives," he said. "If it gets implemented properly, we are going to see some big results quickly as soon as that next severe weather outbreak."

The new system will initially issue more targeted warnings for thunderstorms and tornadoes. Environment Canada said the colour-coded regional warning system will remain in place during a transition period to allow third-party weather platforms to adapt. Broader regional watches will continue unchanged.