EF2 tornado in SW ON on August 17
UPDATE: Additional drone imagery collection and analysis has resulted in several changes to the assessment for this tornado, including the rating, the length and the maximum width. The tree damage caused by the tornado before it reached the houses and businesses at Greenfield Rd. and Northumberland St. has been upgraded to an EF2 rating (the damage that occurred near that intersection continues to be rated EF1). The discussion and event summary for this event has been revised to account for this updated assessment.
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An NTP investigation, including an NTP ground / drone survey, has determined that a tornado hit the Ayr area of southwestern Ontario during the late morning of August 17. The tornado caused EF1 structural damage and EF2 tree damage along a narrow path over 7 km in length and nearly 400 m at its widest. Empty rail cars and a tractor-trailer were overturned, and two trailers were tossed. Thankfully, no injuries have been reported.
More details are available in the event summary below, along with maps and photos from the survey. The tornado can be plotted on a map via the NTP Dashboard .
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Event Name: Wolverton - Ayr, ON
Date: August 17, 2024
Start Time: 10:40 AM EDT (1440 UTC)
Final Classification: Tornado (Over Land)
Final EF-Scale Rating: EF2
EF-Scale Damage Indicator / Degree of Damage: C-T/DOD-6
Start of damage track: 43.2759N, 80.5175W
End of damage track: 43.3073N, 80.4410W
Location of worst damage: 43.2983N, 80.4786W
Description: Witnesses captured video and photos of a tornado that developed near Wolverton and tracked eastward to Ayr. No injuries were reported. Structural and tree damage was reported in the area, including damage to a warehouse building and structures at an agricultural services facility, as well as damage to vehicles. An NTP ground and drone survey was completed on August 17, 2024 documenting the reported damage and additional damage to homes and trees. Satellite imagery review revealed visible tree damage along the path. Damage assessed as EF2 tornado, with an estimated max. wind speed of 190 km/h, track length of 7.33 km and max. path width of 390 m. Tornado motion was from the WSW (approx. 240 degrees). Start time based on radar and witness reports.
Regional map showing the location of the EF2 tornado that occurred between Woodstock and Cambridge, ON.
Survey map showing the track of the tornado toward the ENE as well as the locations of ground and drone photos taken during the survey.
Drone imagery showing the treed area with the EF2 damage. The black box at centre is the sampling box used for the Scalable Box Method of estimating the percentage of trees down, which is required for use of the Canadian EF scale Tree DI. The red lines outline the damage areas, the green line shows the damage centreline and the black line shows the tornado centreline. The houses to the north of the Nith River on Greenfield Road were located just north of the the worst tornado damage.
Drone image showing significant damage to the warehouse roof of a hardware store. One wall collapsed inward. A trailer/boat in the yard was tossed.
Nadir drone photo (up is north) showing trees down from various directions along the path of the tornado.
Ground photo showing empty railcars overturned and a large grain loader arm thrown across them.
Trailer that was tossed from the neighbouring driveway, taking down and landing on a tree in the process. There was no evidence of sliding or dragging, just a large impact mark in the grass where the trailer landed.
Ground photo showing one large tree uprooted from the east (left) and another large tree uprooted from the west (right). A house with structural damage to its roof is shown in the background at left.
