Lightning and Thunderstorms

Environment and Climate Change Canada issues Severe Thunderstorm Watches and Warnings for Ontario based on the following criteria:

• Severe Thunderstorm Watch: When conditions are favourable for the development of severe thunderstorms with one or more of the following conditions:
  • Wind gusts of 90 km/h or greater, which could cause structural wind damage;
  • Hail of two centimetres (cm) or larger in diameter; or
  • Heavy rainfall (i.e. 50 mm or more of rain is expected within one hour)
• Severe Thunderstorm Warning: When there is evidence based on radar, satellite pictures, or from a reliable spotter that any one or more of the following three weather conditions is imminent or occurring:
  • Wind gusts of 90 km/h or greater, which could cause structural wind damage;
  • Hail of two centimetres (cm) or larger in diameter; or
  • Heavy rainfall (i.e. 50 mm or more of rain is expected within one hour)

Environment and Climate Change Canada can issue a “broadcast immediate” alert through Alert Ready for severe thunderstorm warnings that meet the following criteria:

• • wind gusts of 130 km/h or greater;
• • baseball or greater sized hail (7cm).

Check if your cell phone is compatible with the Alert Ready system.

You can also receive local weather alert information by downloading the WeatherCAN app or you can check local weather and forecasts online at www.weather.gc.ca

• Learn to recognize the signs of potential thunderstorms. They are often associated with large, well-defined rising cumulus clouds that have flat bases and dome or cauliflower shapes. As they become darker and more anvil-shaped, the storm is already in progress. Darkening skies, lightning flashes or increasing wind are signs of an incoming thunderstorm.
• Consider purchasing a weather radio or using a weather alerting service available to the public (e.g. WeatherCAN app).
• Consider buying sure protectors, lightning rods or a lightning protection system to protect your home, electronic devices and appliances.
• Cut down and trim trees that may be in danger of falling on your home or vehicle.
• Prepare your home for potential heavy rainfall by clearing drains and eaves troughs, ensuring downspouts empty at least 2 metres from your foundation and checking that your sump pump is working properly including a battery back-up in case of a power failure.
• Ensure loose, lightweight objects outdoors are put away or secured when not in use.
• Create an emergency plan and ensure you identify an interior location within a sturdy building that has no or very few windows in the basement or lowest level where you can shelter. Mobile, manufactured, trailer homes, and recreational vehicles (RVs) are not safe in high winds. If you are in one of these structures, you need to identify a sturdy building nearby that you can get to quickly.
• Plan for power outages as they are often associated with severe weather including thunderstorms. Charge devices (e.g. cell phones, laptops, tablets) prior to forecasted storms and consider installing an alternate power source (e.g. generator).
• Build an emergency kit for your home and vehicle. Severe thunderstorms can disrupt utilities and roadways (e.g. fallen trees, debris) for extended periods of time.
• When the sky looks threatening, turn on your radio and monitor weather reports, or go to the WeatherCAN app or online at www.weather.gc.ca for more information.
• Review your homeowners or renters insurance to ensure you have adequate insurance for your property and personal belongings. Know what is covered, the level of coverage, and the deductible.
• Immediately before the storm hits and it is still safe to so,
  • disconnect electrical appliances such as computers, television sets, appliances and electronics that are charging.
  • put your vehicle in the garage
  • bring pets and livestock to shelter unless there is an immediate risk of flooding
  • close outside windows and doors including garage doors

• "When thunder roars, go indoors." Seek a safe, enclosed shelter immediately if you hear thunder, see lightning or a warning has been issued. Be prepared to seek shelter for a potential tornado or higher speed winds if conditions worsen keeping as many walls as possible between you and the outside.
• Consider the potential for ‘flash flooding’ avoiding low-lying areas.
• Avoid using landline phones. Use battery operated or cordless devices only.
• If inside:
  • Stay away from windows, skylights and glass doors as high winds, debris and hailstones could shatter them.
  • Avoid running and using water (e.g washing dishes, showering, bathing) during a thunderstorm as lightning can enter through pipes.
• If outside:
  • Seek a safe place to shelter such as a home, office, store, or hard-top vehicles with the windows rolled up. Avoid sheltering in open structures such as convertibles, golf carts, porches, gazebos, pavilions and baseball dugouts.
  • If you are swimming or boating get to shore immediately and seek shelter.
  • Stay away from open spaces such as golf courses, parks, playgrounds, ponds, lakes, swimming pools, and beaches.
  • Avoid high elevations and tall structures such as telephone poles, telecommunications towers, and trees as lightning tends to strike the tallest object in the area.
  • If you are caught in an open area, crouch or get low to the ground to reduce the chances of being struck. Avoid lying down though to reduce contact with the ground.
  • Stay away from objects that can conduct electricity such as metal fences, bikes, lawnmowers, tractors, golf carts and clubs.
• Being in a vehicle is safer than being outside. However, if you have time, drive to the closest sturdy building and take shelter inside. If you cannot get to a sturdy building, pull off the road but away from objects that could hit you (e.g. power lines, trees). Avoid touching metal or other surfaces in and on your vehicle.
• Pay attention to local media and alerting systems for current emergency information and instructions.
• It is safe to touch people who have been struck by lightning; they do not carry an electrical charge. To help save their life,
  • Call 911 immediately
  • Move to a safe location if necessary (e.g. away from a tree or open field) but do not move victims who are seriously injured (e.g. major bleeding, potential paralysis, broken bones).
  • Check to see if the person is breathing and has a heartbeat. Perform mouth-to-mouth resuscitation and/or CPR where necessary.
  • Being struck by lightning can cause nervous system damage, broken bones, and loss of hearing or eyesight. Treat injures such as burns, shock and blunt trauma using first aid.

• Check with authorities and weather forecasts for information on whether it’s safe to go outside. Stay inside for at least 30 minutes after the last rumble of thunder.
• Watch for fallen power lines, trees and other debris.
• If there has been heavy rainfall, avoid low-lying areas in case of flash flooding.
• Check on vulnerable family members, friends and neighbours who may require assistance.
• Evaluate your emergency plan and restock your emergency kit.

• Thunderstorms- Emergency Management Ontario
• Thunderstorms- Get Prepared