Cloud seeders scrambled 68 times over southern Alberta this summer, dodging worst hail
Aircraft seeding storms with silver iodide across southern Alberta have had an unusually busy year, though Calgary has largely escaped the golf-ball-sized hail pummelling nearby regions.
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A small fleet of twin-engine King Air C90 aircraft have been scrambled to seed 68 storms over southern Alberta so far this year—an unusually heavy load reflecting a large number of storm warnings and advisories across the region.
"This has been an incredibly busy year," said Adam Brainard, chief meteorologist with Weather Modification International. "Over the last five years, we've had more like 55 or 60 cloud seedings all summer there." The operation covers an area from High River north to Ponoka and from Sundre east to Three Hills, with five aircraft based at Springbank Airport near Calgary and Red Deer ready to deploy on short notice.
The threat has been real. Seven storms with greater than golf-ball-sized hail have been recorded this summer—higher than any prior metric. A normal year sees two or three such storms; a bad year brings four. The largest hail recorded was 8.4 centimetres at Didsbury on July 8. The worst storm to hit central and southern Alberta this summer struck Rocky Mountain House and Clearwater County with hail and two EF2-rated tornadoes.
Calgary, however, has largely dodged the worst. The city sits under five severe thunderstorm warnings so far this summer—compared to six during the same period in 2025. Brainard cites "simply the luck of the draw," noting that fewer storms have threatened the city despite the region's busy season.
The contrast is stark against recent history. A June 13, 2020, hailstorm caused $1.3 billion in insured damages and flash flooding on Deerfoot Trail. An August 5, 2024, storm with baseball-sized hail inflicted $2.8 billion in damage—the costliest hail event in Canadian history—and damaged 17 WestJet aircraft and tore open the roof of Calgary International Airport's Concourse B, with repairs not expected to finish until 2027.
The facts
How many storms have been seeded over southern Alberta this year?
Cloud seeding aircraft have been scrambled 68 times to seed storms over southern Alberta so far in 2026, an unusually heavy workload compared to the five-year average of 55 to 60 cloud seedings per summer.
What's the largest hail recorded in southern Alberta this summer?
The largest hail measured 8.4 centimetres, which fell on Didsbury on July 8, 2026.
How many severe thunderstorm warnings has Calgary had this summer?
Calgary has experienced five severe thunderstorm warnings so far in summer 2026, compared to six during the same period in 2025.
