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Lightning Preparation

What is lightning?

Lightning is an electrical discharge that results from the buildup of positive and negative charges within a thunderstorm. When the buildup becomes strong enough, lightning appears as a bolt. This flash of light usually occurs within the clouds or between the clouds and the ground. A bolt of lightning reaches a temperature approaching 50,000 degrees Fahrenheit in a split second. The rapid heating and cooling of air near the lightning causes thunder.

What is a thunderstorm?

A thunderstorm is formed from a combination of moisture, rapidly rising warm air, and a force capable of lifting air such as a warm and cold front, a sea breeze or a mountain. All thunderstorms contain lightning. Thunderstorms may occur singly, in clusters or in lines. Thus, it is possible for several thunderstorms to affect one location in the course of a few hours. Some of the most severe weather occurs when a single thunderstorm affects one location for an extended time.

Why is lightning a problem in Canada?

  • In Canada, lightning kills about seven people and seriously injures 60 to 70 people a year.
  • Lightning and surge losses cause an estimated $500 million in damage due to electrical and electronic equipment in Canada and the United States each year.
  • The foothills and eastern slopes of southern Alberta are among the most lightning prone areas in Canada, with ½ million lightning strikes per year.
  • There were 40,000 lightning strikes in one day alone during the Edmonton tornado in July 1987.

Interesting facts about lightning

  • The odds of being struck by lightning are 606,944 to one.
  • In the northern hemisphere, two-thirds of strikes occur in June, July and August and mostly in the afternoon.
  • Men are struck by lightning four times as often as women.
  • The typical thunderstorm is 15 miles in diameter and lasts an average of 30 minutes.
  • The average peak temperature of a lightning channel is 27,600°C. The average temperature of the sun's surface is 6,000° C.

Commons myths about lightning

  • Myth: A surge protector provides sufficient protection against a direct lightning strike.

    Truth: No, a surge protector does not provide sufficient protection against a direct lightning strike. A common surge protector will stop voltage spikes and surges, but not the huge, violent burst of current from a close lightning strike. Lightning current is simply too big to protect with a little electronic device inside a power strip. If it needs to, lightning will just jump over your surge protector. Even “disconnects” or devices that physically switch off power to a device by activating a set of contacts, will not guarantee protection. The reason for this is because even an air gap will not stop lightning. Lightning has jumped across miles of air, and won't think twice about jumping a few more inches, or even a few more feet. Not even a full-fledged lightning protection system with rods, cables and grounds will guarantee against damage to electronics and computers.
  • Myth: Lightning only strikes very tall objects, or lightning always strikes the tallest object.

    Truth: Lightning doesn't always strike the tallest and most conductive object. Lightning strikes the tallest objects in a particular area; for instance, if there is a lone small tree in a large field and the field is surrounded by very tall trees, the small tree is just as likely to get hit by lightning as the tall ones. It is also possible for the lightning to strike the ground in the field and completely miss the trees, if the field is large enough. If you are out in the open and are surrounded by tall objects, do not assume you are safe from lightning.
  • Myth: Wearing jewelry, wearing shoes with metal spikes, or carrying metal objects such as tripods, golf clubs and umbrellas will attract lightning and make you more susceptible to a strike.

    Truth: Lightning occurs on too large of a scale to be influenced by small objects on the ground. The only way a small conductive object would influence a lightning channel is if the lightning was already about to strike several feet away. The danger of this myth is that if people assume that something (such as spiked shoes or jewelry) makes them susceptible to a strike, then they may assume that they will be safe as long as they aren't carrying or standing near anything metal.

What do I do during thunder or lightning storms?

If indoors:

  • Secure outdoor objects such as lawn furniture that could blow away or cause damage or injury. Take light objects inside.
  • Shutter windows securely and brace outside doors.
  • Listen to a battery operated radio or television for the latest storm information.
  • Do not handle any electrical equipment or telephones because lightning could follow the wire. Television sets are particularly dangerous at this time.
  • Avoid bathtubs, water faucets, and sinks because metal pipes can transmit electricity.

If outdoors:

  • Attempt to get into a building or car.
  • If no structure is available, get to an open space and squat low to the ground as quickly as possible. (If in the woods, find an area protected by a low clump of trees--never stand underneath a single large tree in the open.) Be aware of the potential for flooding in low-lying areas.
  • Crouch with hands on knees.
  • Avoid tall structures such as towers, tall trees, fences, telephone lines, or power lines.
  • Stay away from natural lightning rods such as golf clubs, tractors, fishing rods, bicycles, or camping equipment.
  • Stay away from rivers, lakes, or other bodies of water.
  • If you are isolated in a level field or prairie and you feel your hair stand on end (which indicates that lightning is about to strike), bend forward, putting your hands on your knees. A position with feet together and crouching is recommended. Do not lie flat on the ground. Remove all metal objects.

If in a car:

  • Pull safely onto the shoulder of the road away from any trees that could fall on the vehicle.
  • Stay in the car and turn on the emergency flashers until the heavy rains subside.
  • Avoid flooded roadways.

Sources include:

  • U.S. National Oceanic and Atmospheric Administration and National Weather Service
  • Insurance Bureau of Canada
    Catastrophic Loss Institute