From: Forbes, Greg
Sent: Tuesday, April 27, 2010 4:07 PM
Subject: long-track tornado perspective

 

I believe that if the aerial survey confirms it to be a continuous path, the 149-mile tornado path Saturday will be the second-longest continuous path known in the United States.

 

Meteorological consensus is that the longest-track tornado known in the U.S. was 219 miles, the Tri-State tornado of March 18, 1925.  Detailed studies of the damage confirm that it was a single continuous-path tornado, and may have even been 15 miles longer than that according to some ongoing historical research.

 

But what is “official” in terms of NWS records will show additional longer tornadoes.

 

Mike Bettes pointed out a paper by McCarthy and Schaefer that mapped the longest-track tornadoes from 1950-2002:  http://www.spc.noaa.gov/publications/mccarthy/tor30yrs.pdf

 

This uses the “official” NWS data that allowed those gaps up to 10 miles (that I have previously emailed about) to be included into a single skipping long-track tornado path classification.

 

I only know of one tornado with path longer than 100 miles from 2003 through last Friday, a 122- mile path in AR on Feb 5, 2008, Super Tuesday.  It was continuous.

 

So, this would be the list of tornadoes with OFFICIAL tracks longer than Saturday’s 149-mile path in LA-MS,

in the 1950-2009 period below.  Tornado historian Tom Grazulis considers all of these to be tornado families, and none longer than 149 mi.

 

235 mi, LA-MS-AR in the 1950-1969 period

218 mi, GA in the 1950-1969 period

203 mi, MS-AL in the 1950-1969 period; this is the 1966 event that most don’t believe

202 mi, MS-TN in the 1970-2002 period; probably Feb 21, 1971

176 mi, NE in the 1950-1969 period

171 mi, OK in the 1970-2002 period

170 mi, KS-NE in the 1970-2002 period

169 mi, FL-GA in the 1970-2002 period

162 mi, MN-WI in the 1950-1969 period

160 mi, NC in the 1970-2002 period

157 mi, IL-IN in the 1960-1969 period

 

NWS in Mississippi also lists a longer tornado prior to 1950 that was longer than the one Saturday.  Grazulis does not believe that to be a single continuous tornado.