February 2009 North American storm complex

February 2009 North American storm complex

Damage in Lone Grove, Oklahoma, caused by an EF4 tornado on February 10
Type	Tornado outbreak, Hailstorm, Winter storm
Duration	February 10–11, 2009
Highest winds	Tornadic: 170 mph (270 km/h) (EF4 Lone Grove, OK) Non-tornadic: 92 mph (148 km/h) (Allegheny County Airport, PA)
Lowest pressure	986 mb (29.12 inHg)
Tornadoes confirmed	14
Max. rating1	EF4 tornado
Duration of tornado outbreak2	26 hours and 26 minutes
Largest hail	4.5 inches (11 cm) in Oklahoma
Maximum snowfall or ice accretion	6 inches (15 cm)
Fatalities	15 fatalities (8 tornadic, 7 non-tornadic)
Damage	$1.7 billion (2009 USD)
Power outages	>2,272,000
Areas affected	Central and Eastern United States
Part of the tornado outbreaks of 2009 1Most severe tornado damage; see Enhanced Fujita scale 2Time from first tornado to last tornado

On February 10–11, 2009, a broad-scale damaging wind event and small tornado outbreak affected the Central and Eastern United States. During the two-day period, 14 tornadoes touched down in seven states. Oklahoma was struck by six tornadoes, the most of any state. The six tornadoes in Oklahoma also tied the record for the most tornadoes ever recorded in the state during the month of February, which would later be broken in 2023.^[1] 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. A tight pressure-gradient behind the cold front led to a large area of damaging non-thunderstorm winds across the Midwest and Ohio Valley. 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 widespread damaging winds left an estimated $1.7 billion (2009 USD) in damage across the Ohio River Valley and Southeastern United States. A small tornado outbreak accompanied the storm, with 14 confirmed across 7 states. The most significant damage occurred in Oklahoma from two tornadoes in the Oklahoma City metropolitan area and a deadly EF4 tornado that destroyed large parts of Lone Grove. The EF4 tornado killed eight people and injured 46 others.