THUNDERSTORMS

THUNDERSTORM - A STORM WITH VISIBLE LIGHTNING AND AUDIBLE THUNDER ON AVERAGE, 1800 THUNDERSTORMS HAPPEN AROUND THE GLOBE DURING ANY DAY.

BECAUSE OF THE TURBULENCE IN A THUNDER CLOUD, THE WATER DROPLETS AND ICE CRYSTALS WILL BREAK APART AND BECOME ELECTRICALLY CHARGED. GENERALLY, THE TOP OF THE CLOUD IS POSITIVELY CHARGED, AND THE MIDDLE AND LOWER PORTIONS ARE NEGATIVELY CHARGED. WHEN THE CHARGES BECOME LARGE ENOUGH, ELECTRICAL DISCHARGES WILL OCCUR.

THE ELCTRICAL DISCHARGE HEATS AIR TO VERY HIGH TEMPERATURES. THIS CAUSES A RAPID EXPANSION OF THE AIR, AND THIS IS THUNDER. THE AIR IS HEATED TO 50,000o F AND LITERALLY EXPLODES.

BETWEEN 75 AND 100 PEOPLE ARE KILLED EACH YEAR IN THE U. S BETWEEN 75 AND 100 PEOPLE ARE KILLED EACH YEAR IN THE U.S. FROM LIGHTNING STRIKES. APPROXIMATELY 10,000 FIRES ARE STARTED BY LIGHTNING EACH YEAR. NASA DISCOVERED A HIGH CORRELATION BETWEEN LIGHTNING STRIKES AND THE AMOUNT OF ICE IN CLOUDS.

LIGHTNING DEATHS BY STATE 1. FLORIDA – 1523 2. MICHIGAN – 732 3. PENNSYLVANIA – 644 4. NORTH CAROLINA – 629 5. NEW YORK – 577 6. OHIO – 545 7. TEXAS – 498 8. TENNESSEE – 437 9. GEORGIA – 410 10. COLORADO – 394 ON A GLOBAL BASIS, RAWANDA IN AFRICA HAS MORE LIGHTNING STRIKES THAN FLORIDA.

LIGHTNING STRIKE DENSITY MAP FROM NASA BASED ON SATELLITE IMAGING.

NASA LIGHTNING STRIKE DENSITY MAP - CONTINUED

TORNADO - A VIOLENTLY ROTATING COLUMN OF AIR IN CONTACT WITH THE GROUND THE U.S. AVERAGES 800 TORNADOES PER YEAR. ONLY ABOUT 1% OF THE 100,000 TUNDERSTORMS THAT OCCUR EACH YEAR SPAWN TORNADOES. RISING WARM AIR AND COOL DOWNDRAFTS COMBINE TO FORM AIR IN A HORIZONTALLY ROTATING TUBE. THIS TUBE CAN TILT AND RESULT IN A TORNADO.

TORNADOES USUALLY FORM ON THE TRAILING EDGES OF STORMS.

WEAK TORNADOES WITH WINDS UNDER 110 MPH ACCOUNT FOR 69% OF ALL TORNADOES AND 3% OF ALL TORNADO DEATHS. THEY USUALLY LAST 6 TO 10 MINUTES.

STRONG TORNADOES (WINDS 110 - 205 MPH) ACCOUNT FOR 29% OF ALL TORNADOES AND 27% OF ALL TORNADO DEATHS. THEY MAY LAST 20 MINUTES OR LONGER.

VIOLENT TORNADOES (WINDS OVER 205 MPH) ACCOUNT FOR ONLY 2% OF ALL TORNADOES, BUT 70% OF ALL TORNADO DEATHS. THEY CAN LAST OVER AN HOUR.

57 DEATHS AND 1,248 INJURIES

WATERSPOUTS - WEAK TORNADOES THAT OCCUR OVER WATER

WHAT TO DO IN CASE OF A TORNADO. GET INTO A BASEMENT, IF POSSIBLE, UNDER STURDY FURNITURE OR A WORK BENCH GET IN A HALLWAY, CLOSET OR BATHROOM - AN INTERIOR ROOM IS BEST IF OUTSIDE, LIE FLAT IN A DITCH AND COVER YOUR HEAD IF IN A MOBILE HOME, GET IN A BATH TUB WITH A MATTRESS OVER YOU

MOST TORNADO DEATHS OCCUR IN AUTOMOBILES AND MOBILE HOMES.

OTHER TORNADO FACTS TORNADOES CAN OCCUR AROUND THE WORLD, BUT THE U.S. IS THE HOT SPOT FOR THE MOST (75% OF ALL). TORNADO FUNNELS ARE ACTUALLY TRANSPARENT. THEY BECOME VISIBLE WHEN THEY SUCK UP DIRT AND DEBRIS FROM THE GROUND OR WATER DROPLETS FROM THE AIR. A FUNNEL CLOUD IS NOT CLASSIFIED AS A TORNADO UNTIL IT TOUCHES THE GROUND.

TORNADO STRENGTH IS MEASURED USING THE FUJITA SCALE. THE SCALE WAS ESTABLISHED BY THEODORE FUJITA, A SCIENTIST AT THE UNIVERSITY OF COLORADO. IT IS BASED ON THE AMOUNT OF DAMAGE DONE ON THE GROUND AND GOES FROM F0 TO F5. THERE COULD THEORETICALLY BE AN F6,BUT IT WOULD BE IMPOSSIBLE TO TELL THE DIFFERENCE BETWEEN AN F5 AND AN F6.

TWO MAJOR TORNADO OUTBREAKS TOOK PLACE IN APRIL OF 2011. APRIL 14 – APRIL 16 – 289 TORNADOES – 45 PEOPLE KILLED – 24 IN NORTH CAROLINA APRIL 25 – APRIL 28 – 305 TONADOES – 318 KILLED “The Tuscaloosa-Birmingham tornado caused at least 65 fatalities. This tornado had a maximum width of 1.5 miles and a track 80 miles long. These are the most fatalities from a single tornado in the United States since May 25, 1955, when 80 people were killed in a tornado in southern Kansas with 75 of those deaths in Udall, Kansas.” http://www2.alabamas13.com/blogs/Alabamas13-Weather-Blog/2011/apr/27/confirmed-tornadoes-impact-metro-birmingham-ar-1771560/