U.S. Severe Weather Blog

How rare was the Oklahoma City-Edmond tornado of 10 Feb 2009?

On the afternoon of 10 February 2009, at least one tornado touched down in northwest Oklahoma City and western Edmond, Oklahoma. A question of interest was how rare this event was.  The question revolves around two issues-the time of year and how far west the tornado occurred.  In mid-February, the greatest threat for tornadoes is in the southeastern United States and there is a strong east-west gradient in tornado occurrence.  I’ve put together a list of all 20 tornadoes that have occurred west of 97.5 W (roughly the longitude of Edmond) in Oklahoma in January or February from 1950-2007.  (As an example of the strong gradient, 38 occurred in the same time period east of the 97.5 W longitude.)  The date and F-scale rating of the 20 tornadoes are in the table below (one tornado was not rated.)  Only once since 1987 has a tornado occurred in the region and time period, and only 2 days have had tornadoes after 1976.  If we restrict our attention to earlier in the year than 14 February, it was the first tornado in the western part of Oklahoma since 1967 and the 5th on record.

2/27/1950 2
2/19/1951 2
2/19/1953 1
1/5/1955 0
2/9/1959 1
2/20/1960 1
2/17/1961 U
2/8/1966 2
1/25/1967 2
2/18/1971 1
2/22/1975 2
2/22/1975 1
2/22/1975 2
2/22/1975 2
2/22/1975 2
2/22/1975 2
2/20/1976 0
2/14/1987 2
2/14/1987 1
2/24/2000 1

(Data source-National Weather Service Storm Prediction Center)

Harold Brooks is a research meteorologist with the NOAA National Severe Storms Laboratory in Norman, Oklahoma.

This blog is intended to facilitate communication about the impacts of selected severe weather events, particularly major tornadoes, in the United States. We hope it will allow us to assist interested parties to understand what we at the NOAA Weather Partners in Norman, Oklahoma have been able to gather about the events. It is not intended to provide critical weather forecast information, nor is it intended to provide information on a broad range of research topics associated with severe weather.