Texas's worst 6-12 month droughts through July 2011 (based on 100 years of data). Brent McRoberts and John Nielsen-Gammon, Texas A&M University via pewclimate.org

By Dan Huber
26 August 2011 Texas climatologists have recently stated that the ongoing dry spell is the worst one-year drought since Texas rainfall data started being recorded in 1895. The majority of the state has earned the highest rating of “exceptional” drought and the remaining areas are not far behind with “extreme” or “severe” ratings by the U.S. Drought Monitor. So far, Texas has only received 6.5 inches of the 16 inches that has normally accumulated by this time of year. Streams throughout Texas are running well below normal and reservoirs are running at 50 percent of capacity. Only one boat ramp remains open between Lake Travis and Lake Buchanan and water levels are falling by a foot per week. For farmers and ranchers who depend on Mother Nature to provide water for their livestock and crops, this lack of water has been crippling. Agricultural losses have already mounted to a record 5.2 billion, and the drought has not yet broken.  Texas has suffered through mega-droughts in the past, so how does the current one compare? Figure 1 shows the year of the worst 6-12 month drought for various areas in Texas. For 55.8 percent of the state, the current drought is the worst on record. No other drought was as bad in so many places. The previous standard for a one year drought, 1925, can now only be considered the worst ever in 14.6 percent of the state. For July, the statewide Palmer Drought Severity Index (PDSI), which is a measure of dryness that takes both temperature and moisture into account, recorded its lowest ever reading. This surpassed the worst July readings for 1918, 1925 and 1956, the droughts of record in Texas. […]

The 2011 Texas Drought in a Historical Context