Thunder Rolls and Lightning Strikes — Summer Weather Safety Tips

According to the National Weather Service (NWS), lightning causes an average of 55 to 60 fatalities and 400 injuries each year. In 2011, there were 26 lightning-related fatalities and 187 injuries reported in the United States. While most lightning injuries occur when people are outside, you may be surprised to know that about 2% happen to people talking on the phone indoors. And the old saying “lightning doesn’t strike twice” is not true — lightning can, and often does, strike more than once!

Lightning Strikes

While a typical thunderstorm is only about 15 miles in diameter, all thunderstorms are dangerous, despite their small size. Lightning damage and injuries cost more than $1 billion in insured losses each year, according to the NWS. There are several warning signs associated with thunderstorms and by knowing them, you can help keep your employees safe:

  • Dark, towering or threatening clouds
  • Lightning and thunder in the distance
    – A lightning strike sounds like a loud, short bang when the storm is nearby, and sounds like a long, low, rumble when it’s in the distance.
  • A sudden drop in temperature

You can estimate your approximate distance from lightning (in miles) by counting the seconds between the flash of lightning and the subsequent sound of thunder, then dividing by five.

Lightning facts and figures:

  • There is no safe place outdoors when a thunderstorm is nearby.
  • Most forest fires in the U.S. are caused by lightning.
  • There are more than 1.4 billion lightning flashes worldwide every year, 8.6 million strikes a day, and 100 strikes per second.
  • The average length of a lightning bolt is six miles and the temperature is 50,000° Fahrenheit —four times the temperature on the sun’s surface.
  • The energy from one lightning flash could light a 100-watt light bulb for more than three months.
  • Florida and the Rocky Mountains are the most lightning-prone areas of the U.S.
  • About 20% of lightning strike victims die, and 70% have long-term health effects.
  • More than 80% of lightning fatality victims are male, typically between the ages of 15 and 40.
  • The rapid heating and cooling of the air near the lightning channel cause a shock wave resulting in the sound we know as thunder.

Tips for staying safe during a thunderstorm:

If working indoors:

  1. Stay away from windows and doors.
  2. Avoid talking on the telephone or using electronic devices.
  3. Be sure to use surge protectors for all electrical equipment.

If working outdoors:

  1. Take shelter in a nearby building or car as soon as you hear thunder.
  2. If you can’t find immediate shelter, get as low to the ground as possible and avoid metal objects, such as bleachers or fences, and water.
  3. Remove all metal objects in your possession (e.g., jewelry, metal shoe cleats, etc.).
  4. Avoid open areas and stay away from isolated tall trees, towers or utility poles.


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