By Mark Shafer, Director of Climate Information
Oklahoma Climatological Survey


NORMAN - Heavy rainfall during March washed away drought from nearly the entire state. This week's Drought Monitor (http://www.drought.unl.edu/dm/) marks the first time since April 5, 2005, that no area in Oklahoma has been designated as Moderate or more severe drought. The rainfall caused flooding problems in much of the state, particularly western and central Oklahoma, but it appears that it was sufficient to erase many of the lingering impacts of a 2-year-long drought cycle.

Across the entire state, topsoil moisture (down to 30 inches) appears replenished, according to measurements from the Oklahoma Mesonet (http://agweather.mesonet.org/soil/). Reservoirs that had shown no change in levels during the 'recharge period' of the water year, beginning last October 1, rose several feet in a matter of hours. Several reservoirs still face lingering impacts and need much more rainfall to fully recover, but they appear to be well on their way if normal rainfall continues. With deeper soils recharged, streams appear to be flowing again and more runoff will make it to the lakes, adding to recharge.

The note of caution on this good news is that southeastern Oklahoma has been creeping into drought since the beginning of the year. Counties in southeastern Oklahoma, which is shown as 'abnormally dry (D0)' on the Drought Monitor, posted the 4th driest February-March totals on record. Other areas of the state that have been stressed by two years of drought will take a while to recover. Pastures that were overgrazed may take a full year or longer to get back to normal production levels. Cattle operations that were forced to reduce their stocks may take years to recover. And, if Oklahoma goes into another hot, dry spring, the recovery could be short-lived.

While it is worth celebrating the return of moisture to the Sooner State, we should take caution in the lesson we learned about how valuable water is to our economy. Oklahoma has seen several multi-year dry cycles in our history (http://climate.mesonet.org/climate_trends.html) and it is not yet certain that the current cycle has ended. Managing our water supplies may be the most important thing we do over the next decades. Conserving water now so that it is there when we need it the next time a drought strikes, whether that is next summer or next decade, may be a good lesson learned.

Figure 1: March Total Precipitation Map