Q: What is the formula for calculating the proximity of lightning using thunder?
A: Light travels at 186,000 miles in a second, sound one-fifth of a mile. Count the seconds between the flash and thunder then divide by 5 to estimate your distance from the strike in miles.
Lightning makes every single thunderstorm a potential killer. Use the 30-30 Rule to determine the lightning threat. If it takes less than 30 seconds to hear thunder after seeing lightning, lightning is still a threat. Wait 30 minutes after last lightning strike before leaving shelter. Half of lightning deaths occur after storm passage.
