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Environment and Climate Change Canada (ECCC) has updated its warning system for tornadoes and severe thunderstorms to allow for more precise warnings about severe weather.
Under the Convective Alert Modernization (CAM) system, forecasters can now issue alerts to specific areas most likely to be affected by extreme weather. ECCC confirmed to CBC Thunder Bay that the updated system is now up and running.
“The forecaster can define the warning area based on where they expect the threat to be, and these alert areas are also known as ‘free-form polygons,'” ECCC said in an email before Tuesday’s launch. “Targeted alert areas are currently only used for severe thunderstorm and tornado warnings. All other weather alerts continue to be issued to pre-determined zone-based areas.
“Using simplified and automated processes, forecasters are also able to provide people in Canada with more precise and actionable information faster than before — in situations where every second counts.”
How the old system worked
Under the old system, storm warnings were issued for larger, pre-determined alert zones, meaning people may receive a warning about a tornado or severe thunderstorm when the storm is unlikely to actually affect them.
David Sills, director of the Northern Tornadoes Project at Western University in London, Ont., said the polygon system has been in use in the United States since 2007.
“It’s great that Environment Canada is finally able to implement this,” Sills said. “The idea is that instead of warning for a county or some other municipal boundary that’s typically large in certain parts of Canada, you’re warning based on the meteorology, based on where the storm is actually going to affect.
“There are all kinds of examples of storms where people in a big city got a tornado warning, for instance, but the tornado was actually in a more unpopulated area of a larger region, and the city really wasn’t going to be affected at all. In that kind of case, it’s going to be the people that are directly affected that will get the warning.”
Sills said the one problem he sees with the new system is that, at this point, the targeted alerts will come via mobile networks and the WeatherCAN app. Radio and television alerts will still use the old system. Environment Canada said that’s because radio and TV broadcast regions are large.
Sills said the system has cut down on false alarms in the United States.
Red tornado warnings have been issued for parts of northwestern Ontario this summer.
In July, for example, warnings were issued for the Kenora, Sioux Narrows, Dryden and Vermilion Bay areas, as a severe thunderstorm Environment Canada said was possibly producing a tornado travelled eastward.
‘People can become desensitized’
In an email to CBC News, Gordon Howard, Kenora’s director of emergency services, said he’s happy to see the ECCC has upgraded the warning system.
“One of the biggest challenges with any emergency notification system is maintaining public trust,” Howard said. “If alerts are issued too frequently or for situations that don’t ultimately pose a significant risk, people can become desensitized and may be less likely to take future warnings seriously.
“At the same time, emergency services are naturally inclined to err on the side of caution. That means there will be occasions when alerts are issued for situations that ultimately do not develop into a significant emergency. It’s a balancing act we face with any emergency notification system, we have to weigh the risk of over alerting against the potentially greater risk of not providing people with enough warning to take protective action.”
Howard said he hopes the new system will see alerts issued when they’re truly needed, which will help keep the public informed and safe “while reducing alert fatigue.”
