What is Lightning?

Lightning is a naturally-occurring phenomenon in which massive, instantaneous discharges of electrical power are produced due to unstable ionic charges between clouds, air, and the ground, resulting in an intense arc of light and a sonic boom (thunder).

Lightning can jump between clouds, or from clouds to the ground.


Lightning Safety

Seek Shelter

Always check the weather forecast when planning activities outdoors. If thunderstorms are forecast, avoid being outdoors at the time, or make alternate plans. Identify safe places for shelter, and determine how long it will take to reach them. As soon as you hear thunder, lightning becomes a hazard.

A safe location is a fully-enclosed building with electrical wiring and plumbing to ground electrical strikes. Do not handle electrical equipment, including landlines, during lightning storms. Tents, picnic shelters, or lean-to type shelters do not protect from lightning.

When Outdoors

If you are caught outdoors and shelter is not available, stay away from tall objects such as trees, poles, and fences. Take shelter in a low-lying area, but be mindful of possible flooding. Lightning tends to strike the tallest object or structure in its path, but the electrical charge can jump. The surrounding ground develops a charge that spreads out and can send current through people and objects in the area.

Squat down onto the balls of your feet and tuck your head into your chest. Try to make yourself as small a target as possible while minimizing your contact with the ground. Do not lie flat on the ground as you will increase your surface area and become a greater target!


Outdoor Activities

It's impossible to predict weather forecasts months in advance. Since thunderstorms can develop quickly, you should always have a weather safety plan ready when planning outdoor activities.

  • Adopt an emergency alerting strategy.
  • Schedule activities for times less likely to receive thunderstorms (i.e. morning).
  • Ensure everyone knows the location of the nearest shelter.
  • Monitor forecasts.
  • Have alternate activities planned, or be prepared to cancel activities.
  • Do not resume activity outdoors until at least 30 minutes after the last thunder.


First Aid for Lightning

  • Lightning victims do not retain an electrical charge; they can be safely handled.
  • Get immediate medical help! Persons struck by lightning may be suffering from burns, shock, or cardiac arrest.
  • If the person has stopped breathing, provide artificial respiration.
  • If the person is in cardiac arrest, administer CPR. If an Automated External Defibrillator (AED) is available, it may be used safely.

Adapted from: Lightning Safety & Preparedness. Government of Canada.


Last revised on 20 September, 2023.