Page:1998-1999 Tornadoes and a Long-Term U.S. Tornado Climatology.pdf/18

92	Apr 16, 1998	1615	TN Wayne Co. - Lawrence Co. Grass/Dirt pulled from ground	3	27	46 miles/1760 yd
93	May 3, 1999	1717	OK Grady Co. - Oklahoma Co. Amber, Newcastle, Moore, Oklahoma City Pavement Removed from Roads Estimated 316 mph winds	36	680	37 miles/1320 yd

Notes about Tornado Classifications

The Fujita Tornado Scale has been used by meteorologists to classify tornado intensities since it was formulated by Dr. Theodore Fujita in 1971. Because it is a subjective damage assessment tool, there are differences in the intensity classifications for individual tornadoes, depending upon the source used. This list depends upon three sources:

1. "Storm Data" Publication (used as a source after 1982 for this report) and the "U.S. Local Storm Reports" Database, by the National Climatic Data Center;
2. National Weather Service's (NWS) National Severe Storm Forecast Center /

Storm Prediction Center WWW page covering tornadoes from 1950 to present;

1. "Violent Tornado Climatography, 1880-1982" by T.P. Grazulis and the U.S. Nuclear Regulatory Commission (NUREG).

Rather than try to reconcile such differences, the above list includes all indicated F5 tornadoes, regardless of the three sources. Differences are noted below.

1. Tornadoes listed as F5 by the NWS, but not by NUREG:
   Numbers: 38, 40, 41, 43, 44, 47, 50, 62, 67, and 75
2. Tornadoes listed as F5 by NUREG, but not by NWS:
   Numbers: 52, 55, 56, 57, 68

There are at least two other tornado data sources (not necessarily independent of those listed above) which may exhibit additional differences. These are the University of Chicago's Damage Area Per Path Length (DAPPL) database and the Tornado Project.

* Damage estimates are derived from the National Weather Service's (NWS) National Severe Storm Forecast Center / Storm Prediction Center web page entitled "The 10 Costliest U.S. Tornadoes." Property damage has been adjusted to 1995 dollars. As with all statistics given on this page, the values are for single tornado events. Only four of the top ten costliest tornadoes were of F5 category; five of the remaining six were F4, and one was F2.

Reference: 1984: Grazulis. T.P., "Violent Tornado Climatography, 1880-1982," NUREG/CR-3670, PNL-5006 RB, U.S. Nuclear Regulatory Commission, Washington D.C., 184 pp.

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