As parts of Canada continue to deal with the aftermath of tornadoes and severe thunderstorms, federal meteorologists are rolling out what they describe as an improved method of issuing weather warning alerts.
If all goes according to schedule, Environment and Climate Change Canada (ECCC) will put the new system into action on its website Tuesday morning.
Federal forecasters said the updated alerts will apply to tornado and severe thunderstorm warnings only. Watches won’t be included. They said the goal is to reduce the number of alerts for severe storms that are unlikely to impact nearby residents.
Under the current system, meteorologists issue tornado and severe thunderstorm warnings to zones often dictated by different governmental and regional boundaries. Some of those zones can stretch up to several hundred kilometres.
“What this means that when we’re issuing one of those two warnings, the alert goes out to a larger number of people than perhaps what the immediate danger really represents,” Jonathan Bau, a senior ECCC meteorologist, told CityNews on Monday.
When the updated system goes live, freeform-polygon figures will follow the storm as it goes. The narrow end of the polygon will indicate where the focus of concern is and will widen out to a projected path either a tornado or a severe thunderstorm that will most likely cause the most impact.
“The polygon will increase in to indicate the uncertainty as to the exact path of the storm, and so this widening of the polygon downstream will again cover a larger area of the population,” Bau said.
“The change to freeform polygons is to reduce the amount of over-alerting.”
As part of the updated system, the website warnings will have a description of the storm location, the direction and speed at which it is moving, a list of locations that could be impacted based on projected time of arrival, and the possible associated weather hazards (for example wind, hail, heavy rain etc.).
ECCC’s alert map will now be able to have multiple layers for warnings and watches, and allow for overlapping depending on what meteorologists have issued.
Despite the improvements, there will still certain restrictions. The polygons won’t be visible on mobile apps like WeatherCAN.
However, when targeted warnings are issued, those will be issued to the National Public Alerting System (also known as Alert Ready). Cellphones in coverage areas within the polygon areas will be able to receive emergency text notifications, and will be more focused on locations most at risk.
The CityNews weather team will have access to the updated warning system, but federal officials noted there will be “marginal” improvements to television and radion interruptions during weather emergencies.
The new method of alerting for tornadoes and severe thunderstorms is the latest in a series of upgrades across Canada to forecasting. Recent changes include a new colour-coded weather alert system and the completion of a new “state-of-the-art” weather radar network.
Dave Sills, director of the Northern Tornadoes Project at Western University, said the improvements come during peak tornado season. He noted parts of southern Alberta and Saskatchewan have seen a noticeable jump in twisters compared to previous years while Ontario is currently below average.
Sills called the ECCC announcement “a good news story” and something many have awaited.
“The people will get cellphone warnings for tornadoes and extreme thunderstorms only if they’re going to actually be affected by them (and) that should really reduce the false alarms,” he told CityNews.
For Sills, he said he and his team have heard the bigger concern for residents revolves around not getting alerts at all or getting alerts after a tornado or severe thunderstorm has passed.
As part of weather radar infrastructure upgrades completed in 2024, the system now conducts scans of the sky every six minutes — down from 10 minutes under the previous technology. Sills said those particular improvements a “big step forward,” adding radar data processing is “very complex” and can take years to perfect.
“The target lead time is only 10 minutes, so that that means a lot has to happen over 10 minutes for people to get that warning and and actually react to it. So every minute counts,” he said, referring to the previous data intervals.
“There are still issues with the quality of the the radar products that are coming out of those new radars, and that’s to be expected with any any new technology that’s being rolled out.
“Radars are particularly finicky about you know how it how they detect things, and it takes quite a long time to really sort out all the issues and get it producing really great data. [Environment and Climate Change Canada] is working on that, and we’re trying to help where we can.”
CityNews chief meteorologist Natasha Ramsahai said the new method of alerts have been “a long time coming,” noting American meteorologists have had access to similar tools for nearly 20 years.
“This is going to be a vast improvement,” she said.
“It’s more precise because it’s no longer region-based. It allows for multiple storm tracking … so you can get multiple polygons and it’s flexible because [federal] forecasters can extend or shorten the polygon as needed.”
Ramsahai said it’s believed the number of alerts for tornado and severe thunderstorm warnings could drop by up to 70 per cent because of the improvements.
