On February 10–11, 2009, a broad-scale damaging wind event and small tornado outbreak affected the Central and Eastern United States.

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.

Strong surface heating combined with cooler air aloft created an unstable atmosphere, a situation unusual in the region for February.

[3] In the afternoon hours, a shortwave trough moved from Arizona into Texas while a strong mid-level jet emanated from the Big Bend region.

[5] Meteorologists expected large hail stones and damaging winds, and recognized the potential for strong tornadoes as thunderstorms developed from central Oklahoma southward into north-central Texas in the afternoon.

[5] The Storm Prediction Center announced a "moderate risk" of severe weather for portions of eastern Oklahoma, northeastern Texas, western Arkansas, and northwestern Louisiana.

It quickly crossed the Red River into Oklahoma and moved through predominantly rural areas, ultimately striking Lone Grove at EF4 intensity.

[7][8] Concurrent with the strong upper-level trough tracking northeastward, the threat for organized severe weather shifted eastward into the Ohio River Valley on February 11, where the Storm Prediction Center issued a Slight risk across much of the region.

[10] Strong forcing along an eastward-moving cold front combined with those wind fields led to the persistence of a low-topped squall line despite little instability ahead of the convection.

[11] Widespread sunshine developed ahead of the squall line throughout the afternoon hours, increasing the potential for strong winds aloft to be transferred to the surface.

As such, the Storm Prediction Center raised the threat level to a Moderate risk across portions of Kentucky, Ohio, and West Virginia for widespread and potentially significant damaging winds.

The organization would ultimately receive over 350 reports of damaging winds on February 11, including a peak gust of 85 kn (100 mph; 155 km/h) near Belle, West Virginia.

[12] By the evening hours, the squall line encountered cooler surface temperatures and became increasingly separated from the powerful upper-level trough, and it lost its vigor moving through the Mid-Atlantic region.

Meteorologists predicted embedded supercell thunderstorms that could produce hail up to 2.5 inches (6.4 cm) in diameter and wind gusts up to 90 mph (140 km/h).

[55] By the morning of February 11, the squall line reached as far southeast as eastern Louisiana, where winds were recorded in excess of 70 mph (110 km/h) along with hail up to 1 inch (2.5 cm) in diameter.

[65] In Arkansas, high winds produced by the squall line knocked out power to 315,324 residences and caused widespread structural damage.

[63]: 81  Strong winds on the backside of the cold front affected large portions of the state, with gusts generally reaching 50 to 60 mph (80 to 97 km/h).

Thousands of trees and power lines were brought down by strong winds and numerous homes sustained significant damage.

In Northampton County, a fire sparked by fallen power lines destroyed a barn and partially melted a nearby metal shed.

Numerous major highways and local streets were shut down for several hours to allow cleanup crews to clear debris.

[44] The storm system continued producing gusty winds through February 12, which caused tree damage and power outages, and killed a construction worker in the New York City metropolitan area.

[44] High winds on the backside of the storm brought down a power line that sparked a small fire in Galloway Township, burning a total of 40 acres (16 ha).

[90] In Massachusetts, gusts up to 55 mph (89 km/h) brought down several trees and cut power to residences in Middleborough, Boston, Brookline and Hingham.

[94] Effects in Georgia were largely limited to scattered instances of downed trees and power lines across northern and central parts of the state.

[63]: 113  One fatality occurred in Kentucky when a utility worker was knocked over by high winds and fell 30 ft (9.1 m) to his death while trying to restore power.

[53] In Montgomery County, Virginia, winds knocked down power lines which sparked two brush fires, one of which burned a total of 12 acres (4.9 ha).

[44] In the wake of the tornado outbreak, law enforcement officers, including 30 National Guard troops, were sent to Lone Grove to assist with rescue efforts.

[100] The Oklahoma City Thunder of the National Basketball Association (NBA) gave away two tickets to anyone who made a donation of $25 or an equivalent amount of food to benefit victims of the tornado.

[104] A concert featuring Chris Cagle and other local musicians at Heritage Hall in Ardmore raised over $18,000 to benefit Carter County tornado victims.