February 2009 Tornado Outbreak

The February 2009 tornado outbreak was a major tornado outbreak that occurred on February 10 and February 11, 2009. It affected portions of both the South Central United States and the Northeastern United States. During the two-day period, 15 tornadoes touched down in seven states. Oklahoma was struck by six tornadoes, the most of any state. The first day of the outbreak produced the most tornadoes; the second brought mainly high wind damage and rain or snow in most of the Northeast.

The storm system responsible for the tornado outbreak resulted from the unusual congruence of a cold, dry system, originating in the Four Corners and a warm, moist system, moving north out of Texas. Complicating factors included daytime heating and a strong wind field favorable to the creation of circulating thunderstorms. On the second day, the stronger cold front limited discrete supercell activity and the risk of tornadoes decreased significantly. A squall line, however, produced high winds and rain along the river valleys, primarily those of the Mississippi and Ohio Rivers. This squall line continued to renew its energy as it passed through the Midwest, Pennsylvania, New Jersey, New York, and New England, causing wind and water damage, and dumping 6 inches (15 cm) of snow in central and eastern Massachusetts. The resulting power outages affected homes throughout the northeastern seaboard.

The most destructive of the weather events, an EF4 tornado now called the Lone Grove Tornado, travelled for nearly an hour through four counties in Oklahoma during the evening of February 10. It destroyed 114 residences in Lone Grove alone. Eight people died and 46 others were injured as a result of the Lone Grove Tornado. It was the deadliest tornado to hit Oklahoma since May 3, 1999 and the strongest tornado during the month of February in Oklahoma since 1950.