Colorado Ranks High on Tornado Charts

Tornadoes are usually classified using the Fujita Tornado Scale, or FScale developed by Dr. T. Theodore Fujita at the University of Chicago in 1971, CDS said. Using FScale classifications, the study looked at whether there was any correlation between tornado strength and frequency of tornadic activity. The study found no “strong correlation between strength and frequency.”

“The areas with the most tornadoes don’t necessarily have the strongest tornadoes,” the report said. “This is true of Florida, which experiences many small tornadoes and waterspouts. In fact, although Florida is ranked third in terms of the number of tornadoes, there were no F-4 or F-5 tornadoes reported during the study period.”

Tornado Events in West States 1990 – 2007

State No. Avg. No. of No. of No F1 F2 F3 F4 F5

of Events Storms/Year Scale Storms Storms Storms Storms Storms Storms

Colorado 809 45 692 93 17 7 0 0

Wyoming 198 11 167 28 3 0 0 0

New Mexico 197 11 176 11 10 0 0 0

California 189 11 144 44 1 0 0 0

Montana 174 10 140 27 7 0 0 0

Idaho 97 5 74 17 6 0 0 0

Arizona 78 4 65 10 3 0 0 0

Oregon 59 3 51 8 0 0 0 0

Utah 56 3 47 7 2 0 0 0

Washington 42 2 33 9 0 0 0 0

Nevada 35 2 31 4 0 0 0 0

Source: CDS Business Mapping LLC

Fujita Tornado Scale

FScale Windspeed(Mph)

F0 40-72

F1 73-112

F2 113-157

F3 158-206

F4 207-260

F5 261-318

Source: CDS Business Mapping LLC

A rural area to the northeast of Denver tops the nation when it comes to metropolitan areas most prone to tornados, according to Boston-based CDS Business Mapping LLC, an online hazard mapping firm (www. cdsys.com).

Yet that same report, published in May 2008 by CDS, noted that Texas had the most tornadoes from 1999 through 2007, with 2,831 events. Seven states – Texas, Kansas, Florida, Oklahoma, Nebraska, Illinois and Louisiana – ranked higher than Colorado in number of tornado events during that time period. On average, Colorado witnesses 45 storms per year, the report indicated.

During the time period examined by CDS the year with the most tornadoes occurring in the United States was 2004, in which 1,944 tornadoes were reported.

Texas leads all other states in the number of tornadoes because of its location and size. Kansas, which ranked second on CDS’ list of most tornado-prone states, leads in the number of F4 and F5 tornadoes. From 1999 through 2004, Kansas had 1,616 tornadoes, 11 of them were F4 tornadoes and 9 were categorized as F5. As Arkansas, Louisiana, Texas and states throughout the Midwest can attest, 2008 is setting a pace to perhaps beat 2004 in recording the highest number of tornadoes for one year.

CDS reported that according to National Oceanic & Atmospheric Administration (NOAA) data, in an average year the U.S. experiences 1,200 tornadoes that kill 55 people, injure 1,500 and cause more than $400 million in damage.

Topics Florida Catastrophe Natural Disasters Texas Windstorm Kansas Colorado