Tornadoes - Autumn (SON) 2009
NCDC added Alaska climate divisions to its nClimDiv dataset on Friday, March 6, 2015, coincident with the release of the February 2015 monthly monitoring report. For more information on this data, please visit the Alaska Climate Divisions FAQ.
The autumn months (Sep-Nov) were relatively quiet across the U.S. in terms of number of tornado reports. There were 7 confirmed tornado reports in September, 69 preliminary reports in October, and 4 in November. The 80 preliminary tornado reports for autumn 2009 is significantly less than the past 3 year (2006-2008) average of 164. The month of November was the quietest such month since 1980, when 3 tornadoes were confirmed. November tied for the 3rd calmest November (also: 1950,1962,1969) since extensive records begain in 1950.
The activity for the month of October occurred primarily across the southeastern U.S., in three separate outbreaks. The state of Louisiana had a very active period with 38 tornado reports. The October 9th outbreak led to 13 preliminary reports primarily in the Tennessee River Valley. The only direct tornado fatality for the season occurred during this series of storms in Washington County, Mississippi. The EF1 tornado was reported to be 100 yards wide and tracked on the ground for 2 miles. The second outbreak was confined to the state of Louisiana on October 22nd when 11 tornadoes were reported. No injuries or fatalities were reported and all tornado reports were EF1 or weaker.
The largest outbreak for the month, driven by a powerful cold front, occurred on October 29th with 35 preliminary tornado reports. The majority of the tornadoes occurred in Louisiana with few reports in Arkansas, Oklahoma, and Texas. There were 16 confirmed tornadoes clustered around Shreveport, Louisiana, with significant damage occurring in the downtown district. This outbreak was the largest for the country since May 13th, which also had 35 preliminary tornado reports, ranking October 29th in the top 5 tornado days of the year-to-date period. Of the tornadoes in this outbreak, only 3 were EF2, and the rest were weaker. There were 10 injury reports and one report of a fatality during the severe weather, but the fatality was determined not to be directly related to a tornado.