A History of Twisters in America

A History of T isters in America HOW MANY AND WHERE Tomadoes are most common in "Tormado Alley" AVERAGE NUMBER OF TORNADOES NUMBER OF RECORDED F3, F4, F5 TORNADOES PER 3,700 SQ. MI (1950-1998) PER YEAR, IN THE U.S. 9 75 31 <1 1 1-5 6-15 18-25 >25 FUJITA SCALE The Fujita scale determines the probable maximum wind speed by the damage associated with a tornado LIGHT Some damage to chimneys; branches broken off trees; shallow-rooted trees pushed over; sign boards damaged. FO MODERATE Peels surface off roofs; mobile homes pushed off foundations or overturned; F1 moving autos blown off roads. CONSIDERABLE Roofs torn off frame houses; mobile homes demolished; boxcars overturned; large trees snapped or uprooted; light-object missiles generated; cars lifted off ground. F2 SEVERE Roofs and some walls torn off well-constructed houses; trains overturned; most trees in forest uprooted; heavy cars lifted off the ground and thrown. F3 Well-constructed houses leveled; structures with weak foundations blown away some distance; cars thrown and large missiles generated. DEVASTING F4 INCREDIBLE Strong frame houses leveled off foundations and swept away; automobile-sized missiles fly through the air in excess of 100 meters (109 yds); trees debarked; incredible phenomena will occur. F5 40 72 112 157 206 260 318 wind speed (mph) THE 15 DEADLIEST U.S. TORNADOES 695 18 Mar 1925 (MO/IL/IN) 317. 06 May 1840 (MS) 255 27 May 1896 (MO) 216 05 Apr 1936 (MS) 203 06 Apr 1936 (GA) 181 09 Apr 1947 (OK) TORNADO PER FUJITA SCALE - 1950-1994 0-RELATED DEATRS - 1950-1 143 24 Apr 1908 (MS) 117 12 Jun 1899 (WI) OF 115 8 Jun 1953 (MI) 25% 74% 114 TORNADO- 11 May 1953 (TX) 29% F4-F5 F2-F3 FO-F1 114 18 May1902 (TX) 1% 67% 103 23 Mar 1913 (NE) 101 26 May 1917 (IL) 100 13 Jun 1944 (WV) 99 18 Apr 1880 (M0) TORNADO SEASON PEAKS IN MAY... Average number of tormadoes by month in the USA (1998-2007) THE 10 MOST EXPENSIVE Billion dollars $1.3 Oklahoma City, 1999 85 AUG APR 157 95 SEP $1.2 MAR 79 63 OCT Wichita Falls, Texas, 1979 69 NOV FEB 28 JAN 39 28 DEC ... AND IN AFTERNOON $1 A.M. P.M. Omaha, Nebraska, 1975 $07 Lubbock Texas, 1970 $0.6 10 Topeka, Kansas, 1966 $0.5 Windssor Locks, Connecticut, 1979 $0.4 St Louis, 1896 $0.4 Xenia, Ohio, 1974 $0.4 North Central Georgia, 1973 ($ 0.4 Worcester, Massachusetts, 1953 THE LIFE OF A TORNADO Astonishing Facts O FUNNEL STAGE The first sign of a tornado may be a rapid rotation within the storm cloud, often in conjunction with the appearance of a short funnel growing from the bottom of the cloud. 1,307 FEET MATT SUTER FROM MISSOURI WAS CARRIED 1,307 FEET BY A TORNADO IN 2006, AND SURVIVED MATURE STAGE The funnel then becomes more organised and descends further from the cloud, touching the ground. 300 MILES PER HOUR DURING THE OKLAHOMA CITY TORNADO IN 1999 WINDS REACHED OVER 300 MPH O ROPE STAGE The tornado commonly moves forward slowly but can travel at speed greater than 100 feet per second. The tornado eventually becomes fragmented and dissipates. 219 MILES THE TRI-STATE TORNADO IN 1925 TRAVELLED 219 MILES IN 3.5 HOURS Inr 601 9 10 11 12 MAY 287