A severe thunderstorm watch was issued for Sarnia-Lambton just after 5:30 p.m. on Wednesday, with a tornado warning following less than two hours later.
Environment Canada warned that the region could see wind gusts near 100 km/h, toonie sized hail, and heavy rainfall. More than 40 mm of rain could accumulate in some areas, the weather agency noted.
Residents are warned that power outages, infrastructure damage, and flash flooding are possible.
At 7:07 p.m., a tornado warning was issued, alongside a warning to take cover immediately if threatening weather approaches.