Orange thunderstorm watch: Golf ball-sized hail possible in Calgary Sunday
Environment Canada issues an orange thunderstorm watch for Calgary; golf ball-sized hail possible Sunday afternoon to early evening. Check alerts; seek shelter.
A Calgary thunderstorm watch issued by Environment Canada warns residents of a high likelihood of severe storms that could bring golf ball-sized hail between Sunday afternoon and early evening. The agency placed the region under an orange-tiered thunderstorm watch, meaning the event is likely rather than imminent. Officials urged Calgarians to monitor updates and be prepared to move indoors if lightning approaches.
Environment Canada issues orange thunderstorm watch
Environment and Climate Change Canada elevated the alert after observing a pattern of damaging hailstorms moving southward from central Alberta. Todd Bate, lead meteorologist with the agency, said warnings are typically issued about thirty minutes before conditions become dangerous. The orange watch signals that the atmosphere is primed for severe hail and potentially significant property damage.
Timing and areas most at risk
Forecasters identified Sunday afternoon through early evening as the window when storms are most likely to impact Calgary and surrounding communities. The watch covers much of the city, with the greatest risk where strong updrafts can support large hail formation. Residents in the path of approaching storms should assume conditions could deteriorate rapidly and act accordingly.
Hail threat could rival 2024 storm
Officials cautioned that the hail may be unusually large and damaging, at times comparable to the destructive 2024 storm that generated more than $3 billion in insurance claims. That earlier event damaged rooftops across the city, including sections of Calgary’s International Airport, underscoring the potential for costly impacts. Environment Canada stressed that while not every storm will reach those extremes, the possibility warrants heightened preparedness.
Meteorological explanation for the threat
Bate attributed the heightened risk to a pocket of cold, turbulent air aloft sliding into the region and creating a highly unstable atmosphere. Warm surface temperatures push moist air upward into that colder layer, fueling strong vertical motion and the formation of hail within storm cells. Where updrafts are sustained, hailstones can grow to large sizes before falling, increasing the danger to vehicles, roofs and outdoor gatherings.
Calgary Stampede activates contingency plans
Calgary Stampede organizers are tracking conditions continuously and have activated their event-specific weather monitoring systems. Kerrie Blizzard, director of public safety and environment at the Stampede, said different events and rides are assessed separately based on their risk profile. Mass notification tools are ready to alert staff, vendors and the public, and organizers can cancel or pause outdoor shows if conditions warrant.
The Stampede emphasized that many attractions are indoors and that teams can restore programming quickly once storms pass. Blizzard encouraged visitors to use indoor options during periods of severe weather and to follow instructions from on-site staff. Safety of patrons and workers remains the primary consideration in any operational decision.
Public safety guidance and preparedness steps
Environment Canada repeated the simple safety rule: when thunder roars, go indoors — a reminder that lightning can be deadly and often precedes the heaviest hail. Residents should secure loose outdoor items, move vehicles under cover if possible, and avoid sheltering under trees. People attending outdoor events should identify the nearest sturdy shelter and be ready to relocate at short notice.
Homeowners and businesses can reduce damage by closing skylights and securing patio furniture before a storm arrives. Those with boats, recreational vehicles or vulnerable equipment should consider relocating or adding protective covers. Local authorities and event organizers will issue warnings as storms evolve; heeding those messages and avoiding unnecessary travel during peak storm hours will lower risk.
As conditions change, Environment Canada will update the public and may issue more severe warnings if storms intensify. Calgary residents, commuters and visitors are advised to keep phones charged, enable severe-weather notifications and follow official accounts for the latest advisories.
Calgarians should treat the orange watch as a prompt to prepare now, not later, and stay alert to rapidly changing weather on Sunday.
