On Lightning Alert

A Dangerous Threat, Avoided

Given lightning’s massive presence and potential for destruction, we have an excellent record of lightning safety in the U.S.  I believe this is a result of four factors, which are described below and listed in order of significance.

  1. Small Target.  Well, it seems that 25 million lightning strikes a year amounts to fewer than seven strikes per square mile of the U.S. each year, on average.  Lightning doesn’t really spread around evenly, but it isn’t generally aimed at people either.  The probability for natural lightning to strike a given point on the Earth’s surface is very low, even in areas of relatively high lightning activity. The key is we don’t make a very big target. The width of the lightning bolt is only about as wide as a pencil, and there may only be a strike or two per square mile during a storm, so most of the time lightning misses…  Of course, standing on or near a bigger target or touching metal or water that conducts an electric charge from a strike on a larger, more attractive target changes the equation dramatically.
  2. Human Nature.  We humans generally disfavor participation in cold, wet, windy, abruptly loud events.  Our dislike for the conditions that breed lightning aids our avoidance of the risk.  We go inside to stay dry, and thus avoid most of the lightning risk; perhaps following the instincts of our distant ancestors who happened upon a good strategy.  Supporting this notion is the fact that most of the lightning deaths and injuries happen just before and just after a thunderstorm even though most lightning flashes occur during the intense portion of the storm.  People instinctively know to avoid the storm; they just don’t always go in quickly enough or stay in long enough.
  3. Modern Infrastructure.  These days, most people live, work, and play in and among sturdy buildings and in vehicles surrounded by layers of natural and man-made lightning rods.  Since 1904 the National Fire Protection Association has published the de facto lightning protection document in the USA (standard for the Installation of Lightning Protection Systems, NFPA-780).  Even a low-end car with metal roof and sides provides reasonably good protection as a sort of “faraday cage” protecting us from the electrical discharge.
  4. Lightning Awareness.  We all have been taught since childhood to beware of lightning.  Technology and advice for staying safe has become more useful in the 275 years since Ben Franklin “proved” that lightning is just electricity.  Our weather scientists have also come a long way in communicating weather & lightning hazard information to the public in the last 170 years since the invention of the telegraph.  While not yet complete, it is a job done well so far.  Thanks!

For most of us, It seems that we’re almost always inside a substantial building or in a metal vehicle, and therefore, almost always sheltered from lightning.  And when we do go outside, most of the time we are so close to a building or a vehicle that escape is moments away.  And due to a lack of thunderstorm steathliness, we almost always know when a storm threatens.

Unfortunately, familiarity tends to breed contempt.  While the rarity of incidents makes it easy to become complacent, sometimes lightning doesn’t miss.  Being hit by lightning is a serious event comparable to a bear or lion attack, resulting in death and life altering injuries.  Lightning injuries and deaths occurring within our modern infrastructure, e.g., parks and open fields around town, baseball and other athletic fields, golf courses, are almost certainly avoidable with minimal attention to basic lightning safety.  Here is an example lighting safety rules developed by the NOAA Lightning Safety Team in 2007 in conjunction with the State of Utah, Lightning Safety Awareness Week.

In my opinion, the most important aspect of recent Expert advice is in helping us where we didn’t know we needed help…by revealing assumptions that we “know” but that are wrong.  In ancient times, the Romans believed that laurel wreaths, sealskin, and sleeping were protective against lightning.  More recently, we have been told and believed we could stay safe by standing in a 45 degree “cone of protection” around a tall object, wearing rubber soled shoes, and by laying flat on the ground to get a low as possible.  And there are more assumptions or other mistakes to beware:

  • Not all “shelters” from rain are safe from lightning:  some shelter options do not protect us from lightning and some make our exposure worse!
    • An isolated tree is a natural lightning rod
    • Unenclosed structures, such as picnic pavilions, rain shelters, bus stops; and insubstantial structures, such as sheds and outhouses, can create additional risks by being tall without offering protection
    • Convertible automobiles, plastics shells on trucks, and vehicles with open cockpits and roofs, like some farm tractors, open construction vehicles, and golf carts provide no protection from lightning
  • Lightning risk is high before and after the storm, not just while the rain is falling
    • Lightning can strike up to 10 miles away from a storm (and sometimes much further)
    • We need to get in a safe shelter before the storm arrives (by the time it is 6 miles away) and stay inside for 30 minutes after the storm passes (let it get at least 10 miles away)
  • Other issues where “common sense” fails us  
    • Not all trees are bad:  an isolated tree is bad, but a dense forest is much better than an open field
    • Never lie flat or sit on the ground to get low; use a crouch position to get low while minimizing contact with the ground
    • Watching nearby lightning can be a shocking mistake; standing on the front porch and standing in front of a window can expose us to lightning hazards
    • Being inside a safe shelter is not enough; lightning can reach inside a shelter via plumbing and wiring.  Don’t take a shower or use other plumbing, and don’t use a corded phone or touch electrical plugs or wires during a thunderstorm

lightning-oddsBut what about us mountain top adventurers who play far outside of the safe, modern infrastructure?  What advice can we use when we play atop the high peaks, far from any substantial building or vehicle?  How much more vigilant do we need to be when the odds of being hit by lightning at some point during our lifetime goes from the U.S. average of 1 in 3,000 to the “one thousand days atop the high peaks” chance of 1 in 15?   I have been hit once in 500 days atop the high peaks; fortunately it was a mild experience.  I’m not planning on testing my luck again.

Unfortunately, there is no definitive, “official” source of instructions for managing lightning risk atop the high peaks.  Research into lightning safety has not been focused on the mountains, but the experts do have useful research-based findings that we can use in our effort to construct a high peaks lightning strategy.  We just need to reconcile the various opinions on where lightning tends to strike in general and on how, probably, we can reduce the risks atop the high peaks.

See Lightning Strategy for more information on forming a strategy to manage lightning risk.

Also, see A Shocking Day on Arapahoe Peak for lightning related trip report


One Response to “On Lightning Alert”

  1. A Shocking Day on Arapahoe Peak « PeakMind Says:

    […] On Lightning Alert […]

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