Quick answer: Alberta’s hail and tornado season runs from May through September and peaks from mid-June to early August. Before a storm, secure loose items, check your drainage and test your sump pump. During a storm, stay indoors and away from windows. Afterwards, keep clear of downed power lines, photograph the damage and cover any openings so water can’t get in.
The Government of Alberta says severe thunderstorms or heavy winds cause the most damage in the province, not tornadoes. Thunderstorms can develop quickly, and a series of them can last for several hours, so the time to prepare is before the warning comes.
Key Takeaways
- Hail and tornado season runs May through September in Alberta, and the Calgary to Red Deer area can expect up to 10 hailstorms a year.
- Most protection happens before storm season: secure loose items, clear eavestroughs, check your grading and test your sump pump.
- If you can see lightning or hear thunder, shelter in a fully enclosed building and wait 30 minutes after the last rumble.
- After a storm, stay at least 10 metres from downed power lines and call 9-1-1.
- Standard home policies cover hail and wind damage, but sewer backup needs optional coverage.
Table of Contents
When is storm season in Central Alberta?
The Government of Alberta says May through September is tornado and hail season, with mid-June to early August the peak. The Government of Canada says the Calgary to Red Deer area can expect up to 10 hailstorms a year.
Recent storms show the range of damage here:
- June 20, 2017: hail and winds over 100 km/h hit Red Deer, Innisfail and Pine Lake. About 35% of Red Deer lost power at the peak, and the city declared a local state of emergency.
- July 18, 2026: two EF2 tornadoes with winds near 190 km/h damaged homes, barns, garages and vehicles near Rocky Mountain House.
- August 23, 2026: hail of about 3.75 to 4 cm hit Springbrook and Gasoline Alley in Red Deer County. The Insurance Bureau of Canada (IBC) puts insured losses at nearly $40 million.
IBC says summer storms across Alberta, Saskatchewan and Manitoba caused more than $1.8 billion in insured losses in 2026.
How do storm warnings work?
Environment Canada now issues severe thunderstorm and tornado warnings for targeted areas rather than fixed zones, so check whether your own location is inside the warning. The most severe storms, with gusts of 130 km/h or more or hail of 7 cm or larger, trigger an emergency alert on phones and TVs. The Government of Alberta also suggests alert apps such as Alberta Emergency Alert.
What damage can a thunderstorm do?
A single storm can bring several hazards at once, and each one affects a different part of your property.
| Hazard | What it can do | What to check afterwards |
|---|---|---|
| Hail | Falls at up to 100 km/h or more, cracks shingles and siding, breaks windows, and can clog storm drains | Roof, flashing, siding, skylights and ceilings |
| Wind | Lifts shingles, breaks windows and brings down trees and branches | Roof, fences, and trees near power lines |
| Heavy rain | A heavy downpour warning means 50 mm or more of rain is expected within an hour, which can flood basements quickly | Basement, floor drains, sump pit and window wells |
| Lightning | Can start fires and damage wiring and electronics | Attic, electrical panel and any smell of smoke |
Not all wind damage comes from tornadoes. Western University’s Northern Tornadoes Project explains that downbursts are strong downdrafts that spread out beneath a storm, often leaving a wide area of damage mostly from the same direction. Our wind damage restoration page covers what to do next, and our hail damage restoration page covers roof leaks and broken windows.
How do you prepare your property?
The Government of Alberta recommends checking the drainage around your home, grading your property so water doesn’t collect or flow toward the house, and making sure you have reliable drainage or a working sump pump. Add these to your spring list:
- Secure or store patio furniture, bins and anything else the wind can pick up.
- Park vehicles under cover when hail is in the forecast.
- Clear eavestroughs, and make sure downspouts are secure and directed away from your foundation.
- Test your sump pump and any backup power.
- Remove dead branches, especially near the house and power lines. Hire a professional near any line.
- Look over the roof from the ground for loose or missing shingles.
- In Red Deer, keep your backwater valve clean and its covers tight. The City warns that removing the covers during a storm will let water into your basement.
Our guide to preparing your home for a major storm has a longer checklist, and our guide to preventing basement flooding goes deeper on drainage.
What should you do during a storm?
The Government of Alberta says all thunderstorms are potentially deadly electrical storms, whether or not a warning is in effect. If you can see lightning or hear thunder, treat it as a threat.
- Go inside a fully enclosed building with wiring and plumbing, and stay away from windows and doors.
- Unplug electrical appliances and stay away from outlets. Avoid electrical equipment and telephones.
- Avoid fireplaces, sinks, tubs and showers, which are more likely to pass electricity.
- If hail starts, keep everyone away from windows, glass doors and skylights.
- If a tornado is near, go to the basement. With no basement, use a small interior room on the ground floor.
- In heavy rain, avoid underpasses, ditches and low-lying areas, which can flood very quickly.
- Wait 30 minutes after the last rumble of thunder before going outside.
What should you do after a storm?
Check for hazards first, then limit the damage.
- Stay clear of downed power lines. Keep at least 10 metres away and call 9-1-1. In Red Deer, then report it to the City’s electric utility at 403-342-8274 during business hours or 403-348-5700 after hours. FortisAlberta customers call 310-WIRE (9473).
- Photograph everything. Take wide and close-up photos and video before anything is moved or covered.
- Stop more water getting in. Alberta’s Insurance Act says you “must take all reasonable steps to prevent further loss or damage.” If it isn’t safe to do yourself, call for emergency board-up and tarping.
- Check inside. Look at ceilings, attics and window frames over the next few days. Our guide to hail-driven water damage explains why leaks can appear later.
- Dry wet areas quickly. Health Canada says mould will begin to grow in an area with excessive moisture within 48 hours. If materials stay wet, see our mould remediation service.
- Notify your insurer. Alberta’s statutory conditions require you to immediately give notice in writing. Keep every receipt.
Does insurance cover thunderstorm damage?
IBC says standard home and business policies cover damage caused by hail or wind. That includes flying debris, falling branches or trees, and water that enters through openings suddenly caused by wind or hail. Pre-existing damage is not covered, and some policies have a separate hail deductible.
Water that comes up from below is different. IBC says basement water damage from a sewer backup is only covered if you bought specific, optional sewer backup coverage. Our post on sewer backup and overland flood insurance explains the difference, and our insurance claim help page shows how we document damage for your adjuster.
Frequently asked questions
How long should I wait after thunder before going outside?
Wait 30 minutes after you hear the last rumble of thunder. The Government of Alberta says to treat any lightning or thunder you can see or hear as a threat.
When is hail season in Central Alberta?
The Government of Alberta says May through September is tornado and hail season, with the peak from mid-June to early August. The Government of Canada says the Calgary to Red Deer area can expect up to 10 hailstorms a year.
Can I use my phone or take a shower during a thunderstorm?
It is best not to. The Government of Alberta says to avoid electrical equipment and telephones during a thunderstorm, and to stay away from sinks, tubs and showers during lightning because these areas are more likely to pass electricity.
Will a severe thunderstorm warning alert my phone?
Only the most severe ones. Environment Canada sends emergency alerts to phones and TVs for severe thunderstorm warnings with gusts of 130 km/h or more, or hail of 7 cm or larger. For other warnings, check the forecast or an alert app.
What should I do if rain starts coming in during a storm?
Stay away from any water near outlets or panels. Move belongings out of the way and catch what you can, then cover the opening once the storm has passed and it is safe. Photograph the damage and call your insurer. Our crews are on call 24/7.
Sources
- Government of Alberta, Thunderstorms, lightning, heavy rain and hail (accessed 2026)
- Government of Alberta, Tornadoes and extreme winds (accessed 2026)
- Government of Canada, Hailstorms (2026)
- Environment and Climate Change Canada, New targeted warnings for severe thunderstorms and tornadoes (2026)
- Insurance Bureau of Canada, Hail and insurance (accessed 2026)
- Insurance Bureau of Canada, Summer storms across Alberta, Saskatchewan and Manitoba cause more than $1.8 billion in insured losses (2026)
- Northern Tornadoes Project, Western University, What is a downburst and how is it different than a tornado? (accessed 2026)
- Northern Tornadoes Project, Western University, Two EF2 tornadoes in southern AB on July 18 (2026)
- Global News, June storm that slammed Red Deer caused over $30M in insured damage (2017)
- rdnewsNOW, Hail pounds parts of central Alberta on Sunday (2026)
- Health Canada, Guide to addressing moisture and mould indoors (2023)
- FortisAlberta, Safety (accessed 2026)
- City of Red Deer, Power Outage (accessed 2026)
- City of Red Deer, Flood Protecting Your Home (2011)
- Alberta King’s Printer, Insurance Act, RSA 2000, c I-3 (2026)