Many people neglect to consider the inherent dangers lightning presents; that is until the sky lights up and an ominous rumble of thunder is heard. The following is a good primer for anyone wanting to learn more about those ferocious bolts of electricity we encounter every summer.
What is Lightning?
Lightning is a visible electrical discharge that occurs within a cloud, between two clouds, or between a cloud and the surface of the earth.
As lightning passes through the air it heats the air quickly. This causes the air to expand rapidly and creates the sound wave we hear as thunder. Normally, you can hear thunder about 20 Km from a lightning strike.
Where, When and How Often Does Lightning Strike?
Average number of thunderstorms on Earth at any given moment: 1,800
Number of times lightning hits the Earth per second: 100
The Foothills and Eastern slopes of Southern Alberta are among the most lightning prone areas in Canada, with a half-million strikes annually.
The Damage Lightning Can Cause: Injuries, Fatalities, Cost
Lightning can occur during any time of the year, but lightning casualties are highest during summer. July is generally the month with the most lightning in Alberta. Lightning strikes often occur in the afternoon and two-thirds of all lightning casualties occur between 12-6pm.
Males are five times more likely than females to be struck by lightning; around 85% of lightning fatalities are men.
People aged 15–34 years account for almost half of all lightning strike victims (41%).
About one-third (32%) of lightning injuries occur indoors.
Environment Canada reports that Lightning strikes injure or kill up to 175 people a year in Canada. It is also conservatively estimated that annual lightning damage and disruption costs in our country range from $600 million to $1 billion every year; almost 6000 insurance claims are predicted to be filed for lightning-related property damage.
Lightning-ignited wildfires cost fire-fighting agencies hundreds of millions of dollars each summer.
What is Lightning Protection?
The highly conductive copper and aluminum materials used in a lightning protection system provide a low resistance path to safely ground lightning’s dangerous electricity. When the lightning protection network is in place, the lightning strike is intercepted and directed to ground without impact to the structure, occupants or contents.
A Lightning Protection System that meets national safety standards includes the following elements:
Failure to make proper provisions for special grounding techniques, or any of the above five elements can result in inadequate protection.
How Effective is a Lightning Protection system?
In January 2003 the American Meteorologist Society issued a Bulletin endorsing the lightning protection requirements, stating:
“It is now well established that properly installed and maintained lightning rod-based protection systems significantly decrease lightning damage.”
In 2001 a joint paper was issued by lightning experts at the U.S. Army, Navy, Air Force, Nat’l Severe Storms Laboratory, Defense Explosives Safety Board, Dept of Energy, NASA and FAA. This paper underscores the critical role that lightning protection systems play in protecting national infrastructure.
Winning the Lottery (with purchase of $3 ticket): 1 in 14 Million
Shark Attack (per year over past 13 years): 1 in 7.9 Million
Winning the “Roll Up to Win” Car: 1 in 7 Million
Injury by Tornado (according to Environment Canada): 1 in 1.7 Million
Getting a Royal Flush in Poker: 1 in 650,000
Being Struck by Lightning: 1 in 260,000
Making a Difference
Environment Canada keeps an updated Canadian Lightning Danger Map (CLDM) on their website that highlights areas that are at the greatest risk of being struck by lightning in the next 10 minutes. (It is based on strikes that have been recorded in the last 20 minutes.) The red areas on the map indicate that lightning is striking there and you are in immediate danger if outdoors.
Lightning-related deaths and injuries have dropped by 80% over the last 75 years. This is partly due to increased lightning safety awareness efforts by partnering organizations like the American NOAA/National Weather service, the Insurance Information Institute, the Lightning Safety Alliance, the Lightning Protection Institute and Environment Canada.