A line of powerful storms that ripped through Alberta and Saskatchewan on Aug. 20 caused widespread wind and hail damage, including at least one confirmed tornado, according to the Northern Tornadoes Project (NTP).
Based on witness accounts, ground surveys and satellite analysis, the NTP has confirmed several distinct events as the long-lived supercell system tracked more than 400 kilometres across the Prairies.
In Alberta, a storm that developed south of Calgary intensified as it moved eastward, striking the Brooks area around 5:15 p.m. MDT. Survey teams documented an EF1 downburst with peak winds estimated at 165 km/h, strong enough to flatten metal transmission towers, collapse farm buildings and kill livestock. Large hail, measuring up to five centimetres in diameter, compounded the destruction.
In Saskatchewan, the system produced a series of damaging wind events after passing north of Saskatoon. An EF1 microburst near Mennon caused extensive damage to grain bins, trees and farm buildings, with top wind speeds near 150 km/h. A second EF1 downburst in the Gruenthal area destroyed barns, toppled silos and killed farm animals along a 22-kilometre track.
Farther east, a weak EF0 tornado touched down near Buffer Lake, damaging trees, grain bins and crops along a narrow 740-metre path. In Aberdeen, a short-lived gustnado scoured a thin line of crops but caused no structural damage.
While no injuries were reported in either province, residents reported significant property losses and widespread hail damage. NTP researchers say further analysis may uncover additional wind events along the storm track.
The Aug. 20 outbreak marks one of the most damaging severe weather days of the season, with scientists noting the storms’ ability to rapidly shift from supercell thunderstorms to organized clusters capable of producing both tornadoes and destructive downbursts.