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Thunderstorms initiate as cumulus clouds, evolving into powerful cumulonimbus formations that can reach heights of up to 70,000 feet. These thunderstorms bring both updrafts and downdrafts, leading to various hazards like lightning, tornadoes, hail, and flash floods, claiming 100-200 lives annually from lightning strikes alone. This guide explores the science behind thunderstorms, the function of lightning, and the connection between thunderstorms and tornado formation, emphasizing the importance of safety during severe weather events.
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This is runaway convection – cumulonimbus over the Plains. These clouds can grow to 70,000 feet (14 miles) high!
Mature thunderstorms have both downdrafts and updrafts. The precipitation forms in the updraft and falls out into the downdraft.
Thunderstorm Hazards Lightning Tornadoes/downbursts Hail Flash Floods
There are actually nine cloud-to-cloud strokes for each cloud-to-ground stroke
In the U.S., the greatest number of thunderstorms and lightning fatalities (5-10 per year) occur annually in Florida.
Notice the segmented pathway to the ground. Also, some of the lighting didn’t contact the ground.
but it often does. In the middle ages, the church towers were used to store gunpowder, with predictable results. Mosques, on the other hand were struck but rarely suffered damage. Can you see why?
Did Franklin really do this? www.codecheck.com/cc/BenAndTheKite.html
“Benjamin Franklin Drawing Electricity from the Sky" by Benjamin West (1738-1820). The Philadephia Museum of Art
The cloud-to-ground stroke heats the air to around 30,000 K, making it the brightest stroke.
By holding the shutter open, several strokes are captured in this image. There were also lots of air discharges.
When the stepped leader’s charge is approaching, you might give off positive streamers! Don’t be the lightning’s conduit. Get inside during thunderstorms.
The fellow inside the metal cage is safe. It’s called a Faraday Cage. Lightning travels around him, not through him.
Inside your vehicle is actually a safe place. It’s a kind of Faraday Cage. Don’t touch the metal parts.
Out on the golf course is NOT a safe place during a thunderstorm.
Lightning in the ground is so hot it will fuse sand. The resulting formations are called Fulgarites
The heating of the air causes rapid expansion. The compession is sound. We hear it as thunder. The sound of thunder travels at right angles to the lightning bolt. It travels at 1100 ft/sec so count to 5. The sound has traveled about one mile.
Blue dots are high winds, Green dots are large hail, Red dots are tornadoes
In 2008, U.S. winds, hail, and tornadoes were concentrated in the summer months.
Tornadoes never occur without a parent thunderstorm. There are over 1000 tornadoes in the U.S. most years.
A large, cone tornado. It might be a mile wide at the ground.
Remarkable image of four tornadoes on the ground at the same time.
The number of tornadoes observed in the U.S. appears to be increasing. Or are we just getting better at finding them?
Tornadoes in the Great Plains tend to be the most destructive
Damage from the May 31, 1998 tornadoes in Albany, NY. On the Fujita scale, where does this fit?
In 2006, the NWS introduced the Enhanced Fujita Scale, a more realistic tool for putting tornadoes into categories.