How do you measure lightning distance?

Question

If I see a flash of lightning and count 5 seconds until I hear the thunder roll----then how far away was the lighting strike itself? I know that there is a crude way to measure how far away a lightining strike is.

There was a thunderstorm early this morning and it made me curious.

Answer 1

I use a stop watch when I am chasing storms to measure the distance. It can be important to chaser. If lighting is seen frequently close to the rain shaft it is likely being generated near the up-draft, down-draft interface which would place it not too far from where the tornado would develop (if one does indeed develop). Gives me a idea of how far I am from where I don't really want to be. I like to use a minimum of 3 mile distance and watch with binoculars. Which works out to about 14 seconds seen to heard time. Less than 14 seconds and I back off or adjust my distance if roads allow depending on movement of the storm.

Since my reaction time is roughly the same for starting the watch with the flash and stopping it upon hearing the thunder, I can get a fairly good time/distance. I use 1128 feet/sec which is based on 70 degrees F. which works out to 344 meters/sec at 21 degrees C. I have used this for over 30 years now and it has kept me at a distance that is reasonably safe in my chases. I still practice lightning safety rules by normally staying in the car for protection from lightning. Anytime you are that close, you are not far enough from the cloud that you are totally safe from lightning.

Answer 2

The simplest way to determine how far lightning is from you is when you see the lightning, count 1001 1002 1003 etc, then when you hear the thunder, every five seconds is one mile so when you hear the thunder and you stop at let's say 1003, you will know that the lightning is less than a mile from you, in this case 3/5 mile for every one second equals 1/5 mile.

Answer 3

Time the thunder. d = v * t t = time for the thunder to realize you, in seconds v = speed of sound, approximately 340 m/sec. d = distance in meters. so as that's extra or less 3 seconds in line with km. As childrens we've been taught to estimate 5 seconds in line with mile. you could start up timing the thunder from once you spot the lightning, applying the approximation that the easy travels immediately. by way of fact it purely takes a fragment of a millisecond, that's close sufficient.

Answer 4

seconds from the sound to the lightning x 330 = the distance of the lightning center in metres (sorry I don't know in miles!)

Answer 5

1 mile per every 5 seconds.