• Southern Ontario Hiking Resources


Lightning is a form of electrical discharge between clouds or between a cloud and the ground.

The discharge may take place between two parts of the same cloud, between two clouds, or between a cloud and the ground. Lightning may appear as a jagged streak, a flash in the sky, or in the rarer form of a brilliant ball. Thunder is the sound waves produced by the explosive heating of the air in the lightning channel during the return.

  • Most lightning strikes occur either at the beginning or end of a storm.
  • The average lightning strike is 10 km long.
  • Lightning reaches 30,000 degrees Celsius, 4X as hot as the sun's surface.
  • A cloud-to-ground lightning channel can be 3 to 16 km long.
  • Voltage in a cloud-to-ground strike is 100 million to 1 billion volts.

Always be on the lookout for the signs of an impending thunderstorm. It’s wise to check the weather forecast before setting out on a hike. Thunderstorms are more prevalent in late afternoon than in the morning.

Lightning can originate from 10 - 13 km away from it's last origin, so it is possible for a "bolt from the blue" on the edge of a storm. This is why if you wait until you see lightning, it may be already too late to take action.


Try to NEVER be out in the open during a thunderstorm.


If you are caught in a thunderstorm in the outdoors there are a number of things you can do to help protect yourself. Remember that there is no 100% safe way to survive outdoors in a lightning storm

  • Move out of open and exposed areas. Ridges, open fields, or nearby tall objects like solitary trees, communication antenna, or rock spires are a bad place to be. Ridges and open fields leave you exposed and as the tallest object around, solitary trees and rock spires serve as natural lightning rods. Stay away from lakes, rivers, beaches where you are in the open and exposed.
  • Unsafe places include underneath canopies, small picnic or rain shelters, outhouses, rock overhangs and shallow caves.
  • If you are hiking as a group spread out at least 6 m apart. Lighting can jump as far as six metres and if you stay close together a lightning strike can injure a group of people.
  • Find an area that is not exposed. A sturdy building or vehicle is best (but likely won't be anywhere around you). Find an area with trees of uniform height or an area with low brush and bushes. Never seek shelter directly under a tree. If you cannot find any shelter at all, say when you are above the tree line, get as low as possible as you can away from any ridges.
  • If you are caught in the open and lightning is nearby, the safest position to be in is crouched down on the balls of your feet. A good bet is to crouch on top of a rock (not the highest one in the area) that is somewhat elevated or otherwise detached from the rocks underneath it. Do not allow your hands (or other body parts) to touch the ground, and keep your feet as close to one another as possible. Why is it important to crouch down on the balls of your feet? The reason why is that when lightning strikes an object, the electricity of the lightning discharge does not necessarily go straight down into the ground. Often the electricity will travel along the surface of the ground for a significant distance. This is known as a "side flash". Many people who are "struck" by lightning are not hit directly by the main lightning channel, but are affected by the side flash as it travels along the surface of the ground (this can be is especially true if the ground is wet). By keeping the surface area of your body relative to the ground to a minimum (that is, keep your feet together and do not allow any other part of your body to contact the ground), you can reduce the threat of the electricity traveling across the ground from affecting you.
  • Alternatively if the above is difficult, sit on top of your pack, if you have one, with your feet together on the ground, crouched down with your eyes closed and your hands over your ears. Sight and hearing injuries are very common among lightning strike victims and near strike injuries. Do not lie prone on the ground, as this is not a safe position.
  • If you have metal gear like a metal hiking stick, lay it on the ground well away from you (at least 6 m).
  • lightning0034Stay away from sharp changes in terrain. Like the edge of water, the edge of a forest, rocks to dirt, the top or bottom of a ravine etc - these areas are naturally more hazardous and lightning tends to follow down the slope.
  • If your hair stands on end, you feel a tingling sensation, or if the area around you appears electrified, lightning may be ready to strike. Keep your ears covered and your eyes closed. Hold your breath, some people have been seriously injured when they breathe in the superheated air that surrounds and is expanding out from a lightning bolt.
  • Wait for at least 30 minutes after the lighting and thunder has stopped to move on and resume activity.  Make sure the storm has left the area.
  • If a member of your party gets hit by lightning start emergency treatment immediately. A person is not electrified after being hit by lighting and a full 80% of people that are hit by lightning recover. If a person has no pulse or heartbeat start performing CPR. Treat electrical burns as you would any other. Neurological and internal injuries are possible. It is also possible for someone to be hit by lightning and be practically uninjured.


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