Residents of Southern Ontario are bracing for severe thunderstorms expected to sweep across the region on April 29, 2025, as Environment Canada warns of dangerous weather conditions. The agency has predicted wind gusts reaching up to 110 km/h, hail measuring between two to four centimeters, and even the possibility of tornadoes.
The weather system, originating from the U.S. Midwest, is anticipated to bring a significant shift in temperatures, with highs soaring into the mid- to high 20s Celsius. Southwestern Ontario could see the first 30-degree day of the year, marking a stark contrast to the recent chilly conditions.
Environment Canada issued a thunderstorm watch for a large area, including Durham Region, extending east to Ottawa and Cornwall, and north of the Greater Toronto Area (GTA) encompassing Barrie, Orillia, and cottage country. Although cities like Toronto, Mississauga, Halton Region, and Niagara are not officially under the watch, they may still experience stormy weather.
According to the forecast, the severe weather is likely to develop between 3 p.m. and 8 p.m. on April 29. "Confidence is increasing in severe thunderstorm development... despite strong forcing to trigger the storms, confidence is moderate due to the possibility of morning convection using some of the energy in the atmosphere," Environment Canada noted in a forecast update.
The potential hazards associated with these storms include large hail and damaging wind gusts, which can cause significant property damage and pose risks to public safety. The alert states that very strong wind gusts can damage buildings, down trees, and even blow large vehicles off the road.
In Haliburton County, residents are still recovering from the effects of a recent ice storm that left over 6,500 homes without power. The Town of Minden has been under a state of emergency since March 31, and in an update on April 28, officials cautioned residents to prepare for further bad weather this week, including concerns about flooding.
Minden Hills Mayor Bob Carter has urged residents to have 72-hour emergency kits ready at home. Suggested items include non-perishable food, water, a battery-powered radio, flashlight, first aid kit, toiletries, cash, and warm clothing.
The Haliburton Highlands OPP is advising residents to stay vigilant during the projected storm. Constable Rob Adams reported that the detachment has received numerous reports of downed power lines and fallen trees, emphasizing the potential for high winds to cause additional damage. "Residents are advised to avoid these hazards... caution is also urged when walking near trees, or when clearing brush... high winds could lead to additional falling trees and debris," Adams said.
In light of the impending storm, officials are also providing flood safety tips. Residents are advised to steer clear of fast-moving water, avoid driving through flooded roads, and remain updated on local weather alerts. Minden Hills residents facing extreme financial hardship due to storm impacts may be eligible for emergency assistance through Ontario’s social assistance programs.
The Weather Network has highlighted that the main hazards with any severe storm that forms will be large hail, strong winds, and heavy downpours. Forecasters also warn of a low, but non-zero risk of isolated tornadoes, particularly if conditions remain conducive to storm development.
As temperatures rise, the public is reminded to stay informed about the evolving weather situation. Environment Canada has advised that there isn’t a safe place outside during a thunderstorm and recommends that individuals take cover immediately if threatening weather approaches.
With the combination of high temperatures and unstable atmospheric conditions, residents across Southern Ontario are urged to monitor forecasts closely and prepare for potential impacts from the severe weather.
