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Monsoon Flooding Threats Continue; Storms Possible in the Mid-Atlantic

Monsoon moisture will primarily stretch from the northern Great Basin to the south and central Rockies. Flash flooding, and mud and debris flows, especially on burn scars will be possible. Strong to severe storms that could produce damaging winds and locally heavy rain will be possible in the Mid-Atlantic, Deep South, and Northeast. Fire weather threats persist for portions of the Northwest. Read More >


A significant outbreak of severe thunderstorms and tornadoes affected a large part of northern, central, and southern Oklahoma during the late afternoon and early evening hours of May 10, 2010. Tornadoes were most numerous across central and southern Oklahoma, with significant damage occurring over many areas.

Severe thunderstorms erupted by mid afternoon across northern and western Oklahoma. Given the potent combination of ingredients in place, storms began to produce tornadoes quickly after initiation. Storm motions of 50 to 60 mph were common. During the mid afternoon hours, severe weather was confined to northern Oklahoma. It was there a long track supercell storm produced tornadoes near the Kansas border - including one rated EF3 - from near Wakita to north of Braman.

Eventually, the capping inversion that had delayed thunderstorm development into central Oklahoma weakened, allowing for explosive supercell development along the dry line along and west of the Interstate Highway 35 corridor. Rapid development and intensification was common with the late afternoon storms, with storms becoming tornadic within a very short time after initiation. This round of storms would directly impact a large part of the Oklahoma City metro area at rush hour, and posed a significant threat to the area. The first tornado in this area occurred in Canadian County.

During the next several hours, tornadoes were clustered around the metro area, and at times there were multiple significant damaging tornadoes occurring simultaneously. Several of the tornadoes had long tracks. Damage from the tornadoes was substantial, with numerous structures, vehicles, trees and power poles/lines significantly damaged or destroyed. One of the more intense tornadoes moved across Lake Thunderbird east of Norman destroying numerous boats.

More storms developed across southwest and south central Oklahoma, and also quickly became tornadic. By 9 pm CDT, 36 tornadoes had been reported in the NWS Norman forecast area. While the loss of three lives was tragic, the casualties could have been much higher given the storm's fast motions, their intensity, the time of day and the areas impacted.

While exact monetary damage figures were not available, it is estimated that losses were in excess of $595 million. At least 450 sustained injuries, most of them minor. Unfortunately, 3 three people lost their lives. Note: The large number of injuries and tornadoes made it difficult to associate injuries with specific tornadoes. Injury numbers were included when there was a strong confidence with the numbers. In addition, the complex nature of storm evolutions and interactions made the job of classifying tornadoes difficult. This represents our best scientific assessment based on ground and aerial surveys, data from multiple radars, photographic and video evidence and anecdotal information.

The National Weather Service in Norman has compiled information on the tornado outbreak that occurred across central Oklahoma on May 10th. Here are some facts:

  • A total of 36 tornadoes have been documented in the NWS Norman County Warning Area, and additional tornadoes occurred in eastern Oklahoma in the NWS Tulsa County Warning Area.  This will be the second largest tornado outbreak documented in Oklahoma (with the largest outbreak occurring on May 3, 1999.)

  • Thirteen different storms produced tornadoes.

  • The tornado damage paths are spread over a north-south area of over 200 miles from near the Kansas-Oklahoma border to near the Red River.

  • Very large hail was reported in several locations, up to the size of softballs (4.25").