By Mark Shafer, Director of Climate Information
Oklahoma Climatological Survey


NORMAN - The newest edition of the Drought Monitor shows significant improvements in drought conditions across Oklahoma. But sometimes pictures don't tell the whole story. While parts of northeastern and north central Oklahoma received more than a foot of snow, this doesn't translate into all that much water. Most areas outside of east central and southeast Oklahoma recorded less than two inches of precipitation from the winter storm. It is welcome moisture, without a doubt, but the nearly two years of drought preceding it means it will take many more events before we can feel comfortable about our water supplies again.

The Drought Monitor is a process that combines direct measurements with advice from local officials. October's rainfall across the southern half of Oklahoma and this most recent winter storm have resulted in near-normal to above-normal precipitation over the last 60 days in all but northwestern and north central Oklahoma. The drought indices used by the Drought Monitor, based on these measurements, suggest that drought conditions in these regions are not that severe.

The difficulty lies in the preceding two years of precipitation deficits. Because the deepest layers of the soil had been so dry for so long, the soil is acting like a dry sponge, absorbing any rainfall and snow melt. Consequently, most area lakes and rivers have shown little response to the recent events. Water supply woes continue, including threatened water supplies such as Lone Chimney Lake in Payne and Pawnee counties and low or entirely dry farm ponds. The exception has been in east central and southeastern Oklahoma, where lakes such as Hugo, Sardis, Wister and Tenkiller are now reported as full.

In most instances, on-the-ground reports help to convince the Drought Monitor authors that the measurements are not accurately reflecting impacts. Despite many attempts this week, the weight seems to be given to the measurements. Therefore, this week's Drought Monitor map should be used with caution. Staff at the Oklahoma Climatological Survey will continue to work with the Drought Monitor authors to get the product back-on-track in future weeks.

For Further Information:

Oklahoma Climatological Survey
http://climate.mesonet.org/rainfall_update.html

Army Corps of Engineers (lake levels)
http://www.swt-wc.usace.army.mil/

U.S. Drought Monitor
http://drought.unl.edu/dm/monitor.html

Oklahoma Mesonet (real-time weather information)
http://www.mesonet.org/

Oklahoma Water Resources Board (Oklahoma Water Resources Bulletin)
http://www.owrb.state.ok.us/supply/drought/drought_index.php

Figure 1: Oklahoma Mesonet precipitation reports Nov. 28 - Dec. 6, 2006