FORT WORTH — The drought that has plagued Texas is virtually certain to continue at least until early summer, climate experts said on Tuesday at a conference in Fort Worth. But what happens after that is anyone's guess.
The main cause of the drought, the most intense in recorded Texas history, is back-to-back episodes of La Niña, a Pacific Ocean phenomenon that almost always brings dry conditions to the state. The bad news is that, based on the historical record, there is a 40 percent chance of La Niña returning for a third consecutive year, according to Klaus Wolter, a research associate with the Earth Research Laboratory at the National Oceanic and Atmospheric Administration (NOAA).
That record consists of 10 instances over the past century in which La Niña has appeared for two years in a row (normally it does not recur). However, Wolter emphasized, 10 episodes is a fairly limited data set. And — here's the good news — the other six times, an El Niño has followed the two La Niñas, bringing unusually wet weather.
"If we were to switch to El Niño next summer, the record of the last decade would indeed favor an end of the 2010-2012 drought," according to Wolter.
Climate experts expect to have publishable insights by June into whether to expect El Niño, La Niña or neither.
Spring is normally the wettest season in Texas, and if the state is to work its way out of the drought, May and June will be "the really, really key time periods," said Victor Murphy, a scientist with NOAA. Temperatures next summer, according to Murphy, are "likely warmer than normal, but not likely to emulate the historic heat of last summer."
The scientists said that low rainfall in the spring does not necessarily signal below-normal rainfall in the summer.
John Nielsen-Gammon, Texas' state climatologist, said ocean conditions today (a cold tropical Pacific Ocean and warm Atlantic) resemble those of the 1950s, when Texas experienced its most severe drought in recorded history. There was one two-year and one three-year La Niña that decade.
The current drought notwithstanding, recent decades have shown trends toward increasing precipitation in Texas, according to Nielsen-Gammon. This is also true in Oklahoma, Murphy said — and it means people are less accustomed to dealing with drought. Since 1980, Murphy said, "we've had an entire generation of Oklahomans who've seen nothing but, literally, wet times."
However, Texas temperatures have been increasing over recent decades, Nielsen-Gammon said, which contributes to evaporation and soil dryness and other factors that exacerbate drought.
Odessa, which has registered 0.77 inches of rain so far this year, the lowest tally of any weather station in the state, is in the running for breaking the all-time record for least precipitation in a calendar year, Murphy said. That record was 1.64 inches, set in Presidio in 1956. Three other West Texas stations — in Kermit, Glenfalls and Wink — have also received less than an inch of rain so far this year, though Murphy stressed that this year's numbers are as yet unofficial.
Eldon White, executive vice president of the Texas and Southwestern Cattle Raisers Association, said that the drought, all told, could end up reducing the cattle inventory in Texas by 12 to 16 percent. As of August, drought had caused some $2 billion in livestock losses, according to an August estimate by Texas AgriLife economists, and given the time that has passed, "it will be bigger," White said.
The good news, White said, is that because ranchers are selling off their less-desirable cows, "we're going to end up with a much higher genetic quality of cattle." Also, he said, the Texas cattle herds will end up being "gentler."
"That old cow that tries to kick you every time you go by her — she's going to be the first to load," he said.