Exceptional Drought Expands in Oklahoma
Associate State Climatologist
Oklahoma Climatological Survey
The extraordinary heat and wind during June has taken its toll on the western half of Oklahoma, allowing the persistent drought that began last fall to intensify and spread. The new map released Thursday morning by the United States Drought Monitor reveals the ugly truth. Exceptional drought, the worst such designation in the Drought Monitor's intensity scale, increased in coverage from 10 percent of the state last week to 33 percent this week. In addition to the widespread exceptional drought covering virtually the entire western one-third of Oklahoma, extreme-to- severe drought has also shifted back to the east.
The state missed a substantial amount of its normal rainfall during the last 30 days. According to data from the Oklahoma Mesonet, the May 24-June 22 statewide average rainfall total was 1.24 inches, a deficit of 3.23 inches and the driest such period in Oklahoma dating back to 1921. Southwestern and south central Oklahoma suffered through similar rankings for the last 30 days, receiving a scant 12 percent of normal rainfall over that period. Since October 1, 2010, some areas in far western Oklahoma have received less than 6 inches of rainfall. Boise City has recorded 2.7 inches of rain in the last 9 months.
The tremendous early summer heat accelerated the drought’s eastward progress. The statewide average temperature for the month thus far stands at 82.7 degrees, which would be high enough to rank as the third warmest June on record in Oklahoma. The warmest June goes to 1953 at 84.6 degrees with 1911 coming in second at 83.3 degrees. High temperatures across the state during June averaged 95.7 degrees through the 22nd, 8.6 degrees above normal. The average high temperature in southwestern Oklahoma came in at 101 degrees during that period. The Oklahoma Mesonet station at Grandfield has recorded a high temperature of at least 100 degrees 20 times during June with a statewide high temperature of 114 degrees on the 17th.
The drought’s impacts have been enormous, especially in western Oklahoma where damage to this year’s winter wheat crop was widespread. Fire danger, which normally subsides in early spring as vegetation greens up, has continued through spring unabated. Damage to the state’s cotton crop in southern Oklahoma is continuing as those plants begin their growth cycle in desperate need of moisture. Livestock operations have been particularly hard hit due to the loss of stock ponds and feed. Cattle sell-offs have continued through spring as ranchers try to thin herds that their land can no longer support.
Very little relief is in sight as the Oklahoma summer continues. The latest outlooks from the National Weather Service’s Climate Prediction Center call for increased chances of warmer- and drier-than-normal conditions through July. The latest U.S. Seasonal Drought Outlook sees persistence or intensification of drought through September for the western one-half of the state.