Lightning the 'deadliest summer weather threat' in Canada

Did you know lightning kills more Canadians than any other weather event? We take a closer look at some of the electrifying facts as a busy thunderstorm season rolls to an end.

Here are some electrifying facts (and fiction) as a busy thunderstorm season rolls to an end

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      It's been a tumultuous year for thunderstorms.

      Big storms have caused damage across the country this season. Just last weekend, much of southern Ontario was under a severe thunderstorm warning. In July, 20,000 Nova Scotia Power customers were left in the dark as lightning strikes fried transformers. That same month, intense thunderstorms swept across the Prairies, causing $48 million in insured damage.  

      • Scroll to the bottom to see the most common myths surrounding lightning

      "It's been a very active year for a summer severe weather point-of-view across all of the Prairies, and specifically in southern Alberta," said Environment Canada meteorologist Brian Proctor.

      Alberta is always an active area, and on average gets 400,000 lightning strikes over the summer. Last year there was 358,753 lightning strikes in the province, but this year that number was up to 576,721 as of Sept. 9.

      The number of severe thunderstorm warnings and watches more than doubled in southern Alberta this summer, and summer storms felt like a daily occurrence in Calgary.

      Calgary saw its fair share of lightning strikes this summer. (Environment Canada)

      The public doesn't always take weather alerts seriously, but Proctor says they should.

      "Lightning is by far the deadliest summer weather threat," he said, adding that's followed by flooding, then "straight-line" wind events. 

      Tornadoes are at the bottom of the fatality list for summer weather events because they are not as frequent. Alberta has one of the most active seasons, and sees on average 10 to 20 tornadoes a season — with many not causing damage.

      Fatal flashes

      "It doesn't have to be a severe storm to potentially kill you, or have impact on you," said Proctor.

      "Every thunderstorm or lightning storm by definition is potentially deadly, but we need a super cell thunderstorm to generate tornadoes."

      Environment Canada says on average nine to 10 people die in Canada each year because of lightning, and another 100 to 150 people are injured.

      Proctor says that number jumps to 57 fatalities in the United States, with roughly 400 a year being struck by lightning. In an average year, lightning kills about the same number of people as tornadoes and more people than hurricanes.

      John Jensenius with the U.S. National Oceanic and Atmospheric Administration (NOAA) told Environment Canada's Canadian Lightning Detection Network that "2016 now ranks as the deadliest year for lightning since 2007."   

      Here's a map of the United States based on known information for lightning fatalities. Florida appears to have seen the most deaths so far this year. (NOAA)

      The NOAA tracks lightning fatalities across the States, but deaths in Canada are a little trickier to find.

      Lyn Mainwaring with the Canadian Lightning Detection Network says she collects as much data as she can, but she says hospitals often classify deaths as a heart stoppage or electrocution.

      Public health organizations, like Alberta Health Services, also don't keep track of the number of injuries or deaths from lightning — instead pointing to the office of the Chief Medical Examiner. CBC's request for information from Health Canada did not get a reply.

      There were several people injured in Alberta this year. Proctor says that includes a group of roofers in Calgary and a member of an Edmonton paving crew who sought shelter under a tree (more on why that's bad later on).

      Environment Canada does collect historical stories of lightning victims, which you can read at length on its website.

      Let me count the ways...

      Environment Canada's advice is, "When thunder roars, go indoors." 

      The national weather agency even provides a lightning danger map that represents the areas most likely to see lightning in the next 10 minutes.

      That's because there are many ways that lightning can kill you, and with an average of two million lightning strikes in Canada each year, there are plenty of chances.

      Environment Canada says that a direct hit from lightning is responsible for only a small percentage of injuries. There are also ground currents, side flashes, being in contact with an object struck by lightning, upward leaders or streamers and shock waves. 

      Here are six ways a lightning strike can kill or injure a person. (Environment Canada)

      "Research shows that a lightning strike that hits the ground is hazardous out to 10 metres," says Environment Canada on its website, which explains each type of danger

      "Some people have been injured 15 to 30 metres away from where a lightning strike has hit the ground." 

      That's because of shock waves on the ground that can throw a person up to two meters, and because of blunt trauma from falling objects, fires and explosions.

      Ever heard of surface arc? That's another concern.

      The graphic above illustrates the surface arc, upward leader and side flash phenomena. (Environment Canada)

      "Ultimately, it is two types of lightning strikes (ground current and side flash) that account for 60 to 80 per cent of all the lightning strikes that see people being killed or injured," says Environment Canada.

      Fact or fiction?

      One of the most common conceptions is that rubber tires will save you from lightning, which Environment Canada says is untrue. It's actually the steel cage of your vehicle that protects you from the current (another reason to skip that convertible ride in a storm) because it provides a pathway for the charge to flow around the vehicle into the ground.

      Proctor says that's actually a problem now for many farmers, as tractors and other large farm equipment traditionally made out of steel are being replaced with materials like fibreglass and plastic.

      Don't stand under a tree in a storm. Instead seek shelter in a structure that has plumbing (as it helps dissipate the charge into the ground).

      If you're in a field or camping, and have no access to shelter, Proctor suggests you get low with your feet close together, crouching on the balls of your feet, with your hands tucked behind your head.

      Here are some of the other most common myths surrounding thunderstorms from Environment Canada:

      • Rubber boots won't save you: Rubber-soled shoes and rubber tires provide no protection from lightning. The lightning strike between the cloud and the ground has potentially travelled thousands of meters through thin air, therefore rubber soled footwear or tires are inconsequential.
      • If it's not raining, there is no danger: Lightning often strikes outside of heavy rain and may occur more than 16 kilometres away from a storm. If you can hear thunder, you are at risk of being struck by lightning and should take shelter immediately. Remain sheltered for at least 30 minutes after the last rumble of thunder.
      • People struck by lightning carry an electrical charge: Lightning-strike victims carry no electrical charge and therefore can and should be attended to immediately.
      • "Heat lightning" occurs after hot summer days and is not a threat: "Heat lightning" is actually just lightning from a thunderstorm that is too far away for thunder to be heard. However, it does mean that the storm may be moving in your direction.
      • Blue skies mean no threat: If you hear thunder, then the lightning is close enough to pose an immediate threat.
      • Being indoors guarantees your safety: Stay away from electrical appliances — that means your computer, TV or gaming console if plugged in — and equipment, doors, windows, fireplaces and anything else that will conduct electricity, such as sinks, tubs and showers. Only use a corded telephone in an emergency. 

      About the Author

      Rachel Maclean


      Rachel Maclean is an award-winning journalist who joined the CBC Calgary team in 2011. She now works as the newsroom's social media guru, and can be contacted at


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