Tornadoes - October 2010
October was a very active month in terms of the number of preliminary tornado reports. According to the Storm Prediction Center (SPC), there were 120 preliminary tornado reports across the U.S. during the month. The final tornado count will likely be less, but the final count will likely rank the month in the top five most active Octobers on record. Despite the active month, there were no fatalities reported. The most active October was in 2001 when there were 119 confirmed tornadoes. The majority of tornadoes were associated with two storm systems that brought severe weather to the Midwest, Southeast, and Southwest.
A major severe weather event struck northern Arizona on October 6th, with at least eight confirmed tornadoes in the state. This marks the most tornadoes to strike the state in a single day since reliable records began in 1950. Arizona on average receives four tornadoes annually. Not only was the number of tornadoes impressive, but several of the tornadoes were damaging and long tracked events. The tornadoes were associated with a strong low pressure system over California bringing moist air from the south. According to the National Weather Service, it was the combination of extremely strong vertical wind shear, instability, and the vertical forcing of a shortwave that produced the severe weather outbreak. Visit the Global Hazards page for additional information.
A multi–faceted and record–breaking low pressure system moving across the Northern Plains was associated with a strong cold front stretched across the Midwest, Southeast, and Mid–Atlantic, creating severe weather on October 26th and 27th. According to the SPC, the two day preliminary tornado count stands at 75 (the final tornado count will likely be less). Tornadoes were reported from Wisconsin, southward to Alabama and eastward to Maryland. Fortunately, none of the tornadoes of the outbreak were rated higher than EF-2 and there were no fatalities reported. The tornado count could potentially break the October record for number of tornadoes associated with a single outbreak. A severe weather outbreak in October 2007 brought 62 tornadoes to the U.S. and currently holds the record for most tornadoes during an October outbreak.