The Old Farmer’s Almanac predicts that today’s 4th of July festivities will bring fireworks in the sky … from thunderstorms! In honor of nature’s fireworks, we are taking a look at some thunder lore and how thunder is born!
Thunder is born in the instant when the return lightning stroke leaves the earth and spears upward through the channel of ionized air. The channel is viciously expanded outward and bursts in the sonic shock wave that reaches up as a thunderclap. This initial sound is followed by a rumble as the thunder echoes through the sky. The sound of thunder always reaches us after we see the lightning flash because light rays travel at 186,282 miles a second while sound waves (the speed of which varies with such factors as temperature) lope along at somewhere between 1,000 and 1,100 feet or so per second. This difference in speed enables us to tell just how far away the lightning is striking. All that needs to be done is to count the seconds between the flash and the initial thunderclap. For every 5 seconds that elapse, the lightning is about 1 mile away.
Unlike general rain, thunderstorms move in so quickly and then depart with such haste that their arrival and length of stay can not be forecast much in advance. But there are a few predictions that refer to what will come in their wake, and at least one of these smacks of the truth:
When it thunders in the morning, It will rain before the night.
Thunder predictions often concern themselves with what the storms may to do a farm crop:
Thunder in March betokeneth a fruitful year.
When April blows her horn [thunders],
It’s good for both hay and corn.