Environment Canada is transitioning from zone-based Tornado Warnings and Severe Thunderstorm Warnings to a new system of storm-based warnings. These warnings will be targeted specifically by forecasters based on the storm’s location and direction. The United States has been using storm-based warnings for the past 19 years, and an update to Canada’s system has been much sought-after by forecasters. Adam Skinner of Instant Weather Inc. noted that Environment Canada has been attempting to implement the new system for two years, but various setbacks have delayed its rollout.
Under the old system, storm warnings were issued for larger, pre-determined alert zones, which in Saskatchewan often followed municipal boundaries. This resulted in people receiving warnings about a tornado or severe thunderstorm even if the storm was unlikely to affect them. The new system, called Convective Alert Modernization (CAM), launched this week. This change is expected to reduce the number of people automatically receiving these warnings, with the greatest improvement seen in rural communities where previous alert zones were massive. Excessive warnings can lead to ‘warning apathy’ or ‘alert fatigue.’ In Waldheim, for instance, several residents reported ignoring the warnings after previous alerts did not result in actual tornadoes.
In the new system, an Environment Canada forecaster will now draw a shape known as ‘free-form polygons’, enclosing where the storm is currently and where it is expected to travel based on the path it has been following and other environmental factors, including other storms that may be in the area. The free-form polygons will be used to target the alert sent to cell towers. The new warning system will continue to notify phones outside of the actual alert area if a phone is within the reach of the cell phone towers within the alert area. However, radio and television alerts will only see marginal improvements, and people at a significant distance away from the storm’s path may still receive notifications.
These changes apply specifically to tornado and severe thunderstorm warnings, where timing and distance can significantly impact outcomes. All other types of alerts, including warnings for winter storms, rainfall, heat, and air quality, will continue to be issued using the existing zone-based system. The new free-form polygon alerts are an addition to, not a replacement for, the large municipality and county-based alerts. In the event of a failure in the storm-based warning system, the old system will still be utilized.
Historical data from the Northern Tornadoes Project indicates that less than 10 percent of severe thunderstorms produce tornadoes. Nevertheless, forecasters will continue to issue warnings whenever the potential for one exists. As of August 7th, 87 tornadoes had been confirmed across the nation, with more than 70 occurring in Alberta, Saskatchewan, and Manitoba.
According to information shared with independent forecasters, tornado and severe thunderstorm warnings will currently be issued based on both the zone-based and the new storm-based system. This dual approach ensures that those in potential danger are informed of the approaching storm. Additionally, AlertReady, the system used for issuing Amber Alerts and other mass notifications, will utilize the storm-based warning system.
An absence of alerts does not guarantee safety in your vicinity, Skinner cautions. Effective alerting is most beneficial when combined with situational awareness rather than serving as a substitute for it. When an alert is received, take it seriously. Monitor both the sky and radar, as notifications alone may not provide a complete picture of potential threats.
By Carol Baldwin, Local Journalism Initiative Reporter
Original Published on Aug 14, 2026 at 07:00
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