Thunderstorms, lightning, heavy rain and hail

Overview

Thunderstorms, lightning, heavy rain and hail can develop quickly and threaten life and property. Severe storms occur frequently across Alberta and can be unpredictable.

See the following fact sheets for more information:

• Thunderstorms, lightning and hail
• Severe weather
• Tornadoes and extreme winds
• Shelter in place: severe weather
  (these fact sheets are available in several languages at the bottom of this page)

Thunderstorms

All thunderstorms are potentially deadly electrical storms, whether or not there is a severe weather warning in effect. Severe weather can bring damaging conditions such as strong winds, hail, lightning, heavy rain and tornadoes.

• A series of thunderstorms can last for several hours.
• Severe thunderstorms or heavy winds cause the most damage in Alberta, not tornadoes.
• Thunderstorms can bring hazards such as heavy rain, lightning and hail.

What to do before and during

• Before a thunderstorm, pay attention to local news and weather reports for up to date information on thunderstorm conditions, weather warnings and storm maps.
• Secure loose objects outdoors in case of strong wind and cover your vehicle in case of hail.
• During a thunderstorm, move to a safe place that is away from windows and doors. Avoid using electrical equipment and telephones.

Lightning

Each year lightning kills approximately 10 Canadians and injures many more. On average, lightning causes more fatalities in Canada than hail, rain, flooding, wind, tornadoes and hurricanes combined.

What to do before and during

If you can see lightning or hear thunder:

• Consider it a threat.
• Seek shelter in a fully enclosed building with wiring and plumbing.
• Unplug electrical appliances and stay away from outlets.
• Avoid windows, doors, fireplaces, sinks, tubs and showers because these areas are more likely to pass electricity.
• Wait 30 minutes after you hear the last rumble of thunder before going outside.

If stranded outdoors:

• Avoid standing near tall objects or anything made of metal.
• Avoid water and take shelter in a low-lying area, such as a ditch.
• If you are out on a lake or other body of water, make way for shore immediately and then follow the instructions above.
• If possible, avoid sheltering in your vehicle. It does not offer significant protection from lightning.

Heavy rain

Heavy rainfall can cause floods in a short period of time, especially when the ground is frozen or already wet. A heavy downpour warning is issued when 50 mm or more of rain is expected within one hour.

What to do before and during

Before heavy rainfall:

• Check the drainage around your home to see if there is any possibility of your basement flooding.
• Take preventative measures such as grading your property so water does not collect or flow towards your home.
• Ensure you have reliable drainage or a working sump pump in your basement.

If outdoors during heavy rainfall:

• Avoid roadway underpasses, drainage ditches, low lying and water collection areas. These areas can flood and overflow very quickly.
• Stay away from power lines and electrical wires.

Hail

Hail forms in storm clouds and is most common in summer, but can also occur during colder times of the year. Hailstones range in size, from small peas to grapefruits, with large hail occurring more in the warmer season.

• Hailstones can fall at speeds of up to 100 km/h or more, and can cause significant damage to homes, property, cars and crops.
• When combined with heavy rains, hail can clog storm drains leading to flooding.

What to do before and during

• Immediately take cover when hail begins to fall.
• Keep yourself and your loved ones away from windows, glass doors and skylights.
• If outdoors and there is no shelter close by, crouch down with your face away from the wind. Protect your neck with your hands.

Videos

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Related

• Emergency preparedness
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