Downbursts in Mattawa, ON and Huntsville, ON areas with May 18 storms
After thorough ground, drone and satellite surveys, the NTP confirms that four EF0 downbursts occurred in the Huntsville, ON and Mattawa, ON areas with the storms of May 18. One injury was reported with the Mattawa damage while four injuries were reported with the damage in Algonquin Park. According to the OPP, one tragic fatality occurred with a falling tree south of Huntsville - there wasn't enough tree damage at that area to be assessed as a downburst.
Additional details are provided in the event summaries below, along with a regional map, survey summary maps, and several photos. The events can also be plotted on a map using the NTP Dashboard .
Reminder: a 'microburst' is a type of downburst - brief, intense and covering an area less than 4 km across.
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Event Name: Mattawa, ON
Date: May 18, 2026
Start Time: 8:00 PM EDT (0000 UTC)
Final Classification: Downburst
Final EF-Scale Rating: EF0
EF-Scale Damage Indicator / Degree of Damage: C-T/DOD-3
Location of worst damage: 46.3115N, 78.7166W
Description: Tree damage was reported in and north of Mattawa after a storm passed through the area. One injury was also reported. An NTP ground and drone survey was completed on May 21, 2026, documenting the reported damage along with minor damage to a warehouse building. A preliminary review of satellite imagery revealed intermittent weak damage over the area. Damage assessed as EF0 downburst, with an estimated max. wind speed of 115 km/h, with damage occurring over an area at least 8 km long and up to 6 km wide. Start time is radar estimated.
Event Name: Huntsville, ON
Date: May 18, 2026
Start Time: 8:40 PM EDT (0040 UTC)
Final Classification: Downburst (microburst)
Final EF-Scale Rating: EF0
EF-Scale Damage Indicator / Degree of Damage: C-T/DOD-3
Location of worst damage: 45.2979N, 79.2970W
Description: Tree damage was reported in the Huntsville area after a storm passed through. An NTP ground and drone survey was completed on May 20, 2026, documenting the reported damage. A preliminary scan of satellite imagery revealed isolated visible damage. Damage assessed as EF0 microburst, with an estimated max. wind speed of 115 km/h, with damage found over an area approximately 2.2 km long and up to 0.3 km wide. Start time is radar estimated.
Event Name: Baysville, ON
Date: May 18, 2026
Start Time: 8:45 PM EDT (0045 UTC)
Final Classification: Downburst (microburst)
Final EF-Scale Rating: EF0
EF-Scale Damage Indicator / Degree of Damage: C-T/DOD-3
Location of worst damage: 45.1583N, 79.1057W
Description: Tree damage was reported near Baysville after a storm passed through the area. An NTP ground and drone survey was completed on May 20, 2026, documenting the reported damage. A preliminary scan of satellite imagery revealed isolated visible damage. Damage assessed as EF0 microburst, with an estimated max. wind speed of 115 km/h, with damage found over a limited area approximately 0.5 km long and up to 0.3 km wide. Start time is based on witness report and radar imagery.
Event Name: Lake of Two Rivers, ON
Date: May 18, 2026
Start Time: 9:20 PM EDT (0120 UTC)
Final Classification: Downburst (microburst)
Preliminary EF-Scale Rating: EF0
Location of worst damage: 45.5778N, 78.5002W
Description: Tree damage was reported in the Lake of Two Rivers area after a storm passed through. Four injuries were also reported at local campgrounds. Satellite imagery review revealed isolated visible damage. Preliminary EF-Scale rating is EF0, with further investigation pending to finalize the estimated max. wind speed. Start time is radar estimated.
Regional map showing the locations of the four EF0 downbursts.
Damage survey summary map for the EF0 downburst at Mattawa, ON.
Damage survey summary map for the EF0 microburst at Huntsville, ON.
Damage survey summary map for the EF0 microburst at Baysville, ON.
Drone photo of multiple trees down within the Mattawa, ON EF0 downburst.
Photo of multiple trees blown over within the Huntsville, ON EF0 microburst.
Drone photo of multiple trees down within the Baysville, ON EF0 microburst.
