Lightning Distance Calculator

How It Works

Sound travels approximately 1 mile every 5 seconds (1,125 ft/sec). The "30-30 Rule": if the flash-to-bang time is 30 seconds or less (6 miles), seek shelter immediately. Stay sheltered until 30 minutes after the last thunder. Avoid ridgelines, tall trees, and open water. In the backcountry, crouch on an insulating pad in a low area away from tall objects.