The National Lightning Safety Institute recommends the following TWO swimming pool safety procedures:

  1. When thunder and/or lightning are first noticed, use the Flash-To-Bang (F-B) method to determine its’ rough distance and speed. This technique measures the time from seeing lightning to hearing associated thunder. For each five seconds from F-B, lightning is one mile away. Thus, a F-B of 10 = 2 miles; 15 = 3 miles; 20 = 4 miles; etc. At a F-B count of thirty, the pool should be evacuated. People should be directed to safe shelter nearby.
  2. Pool activities should remain suspended until thirty minutes after the last thunder is heard. The distance from Strike A to Strike B to Strike C can be some 5-8 miles away. And it can strike much farther away. Why take a chance with lightning?

WE TAKE THUNDER + LIGHTNING + POOL VERY SERIOUSLY. 

If you can see it, flee it; if you can hear it, clear it.