Lightning Safety Guidelines

Lightning Safety Guidelines

(Adapted from NCAA Recommendations)

General Guidelines

  1. Each department should develop a lightning safety plan.
  2. Designate a person to monitor threatening weather and to notify the chain of command

        a. Prearranged instructions

        b. Announcements for personnel

        c. Designation of warning and all-clear signals

        d. Proper designation of safer places

3. Be informed of National Weather Service issued thunderstorm watches or warnings and know the difference

4. Know where the closest safer structure or location and how long to get there

        a. Any building normally occupied or frequently used by people

        b. In the absence of a sturdy, frequently inhabited building; any vehicle with a hard metal roof (neither a convertible nor golf cart) with the windows shut.

            i. The hard metal frame and roof, not the rubber tires are what protect occupants by dissipating lightning currents around the vehicle and not through the occupants.

Lightning Safety Plan

  1. As a minimum, lightning safety experts strongly recommend that by the time the weather monitor observes 30 seconds between seeing the lightning flash and hearing its associated thunder or by the time the leading edge of the storm is within 6 miles, all individuals should be within a safer structure.
  2. Thunder may be hard to hear if there is an event going on or loud equipment is being operated.
  3. Planning should account for the time it takes to move personnel to their designated safer areas.
  4. Lightning can strike from blue sky and in the absence of rain.   At least 10% of lightning occurs when there is no rainfall and when blue sky is present; this is especially prevalent with summer thunderstorms.  Lightning can and does, strike as far as ten (or more) miles away from the rain shaft.  If you hear thunder, lightning is close enough to pose an immediate threat.
  5. To resume activities, lightning safety experts recommend waiting 30 minutes after both the last sound of thunder and after the last flash of lightning is at least 6 miles away and moving away.
  6. People who have been struck by lightning do not carry an electrical charge.  Therefore CPR is safe.  Call DPS at 911 and activate your emergency action plan.  Prompt, aggressive CPR has been highly effective for the survival of victims of lightning strikes.
  7. AED’s are a safe and effective means of reviving people in cardiac arrest.

Flash to Bang Method

To estimate the distance between your location and a lightning flash use the “Flash to Bang” method.  If you observe lightning, count the number of seconds until you hear thunder.  Divide the number of seconds by five to obtain the distance in miles.

If Thunder is Heard* The lightning is...
5 seconds after a flash 1 mile away
10 seconds after a flash 2 miles away
15 seconds after a flash 3 miles away
20 seconds after a flash 4 miles away
25 seconds after a flash 5 miles away
30 seconds after a flash 6 miles away
35 seconds after a flash 7 miles away
40 seconds after a flash 8 miles away

*Because lightning can strike up to 10 miles from a storm, you should seek safe shelter as soon as you hear thunder or see lightning.  Get to a safe location if the time between the lightning flash and rumble of thunder is 30 seconds or less.


Revised 9/2020