Two consecutive years of La Niña events in the Southern Hemisphere, an unusual development, are credited with causing the worst drought in Texas history. But NOAA forecasters are saying there is a 40-percent chance for an even rarer third round of the Pacific Ocean phenomenon next year and that could add to the devastating $5.2 billion in loses to state agriculture.
Klaus Wolter, a research associate with the Earth Research Laboratory at the National Oceanic and Atmospheric Administration (NOAA), says a La Niña event causes colder-than-normal water in the lower Pacific Ocean and warmer-than-normal conditions in the Atlantic. The result for Texas farmers and cattle raisers is unusually dry conditions.
“La Niña generally brings drier conditions to Texas, like what we are seeing now. Two or three consecutive years of dry conditions can have a devastating impact not only on agriculture but on the recharging of aquifers and reservoirs. This could spell real disaster for an industry that is already suffering and would cause widespread water shortages that would be hard to overcome,” Wolter said.
If there is any positive news it is that often an El Niño follows a La Niña event, and traditionally this brings exceptionally wet weather to the region.
“If we were to get an El Niño event this next year instead of a La Niña, we would be more worried about flooding of cropland than we are about the drought. But statistically we are more likely to see a third year of drought,” he added.
Back-to-back La Niña events are unusual, having happened only ten times in the last 100 years, according to Texas State Climatologist Dr. John Nielsen-Gammon, and only five of those developed into a third year La Niña, the last time happening in the 1950s.
Nielson-Gammon says climate experts are collecting data now and are expected to publish their findings by next summer, which will indicate whether the drought will see a third consecutive year of drought or if El Niño will bring much needed rain to a parched Southwest.
But even if a third consecutive year La Niña develops, forecasters say another active year of heightened tropical weather, which often results from La Niña years, could possibly bring rain relief to Texas, much the same as it did for South Texas in the summer of 2010.
“In that year extreme South Texas received substantial rains that replenished reservoirs and groundwater,” says Dr. Robert Mace, deputy executive administrator of the Texas Water Development Board. “And in spite of another year of drought, the forecast is calling for less extreme heat next summer, which will also help to curtail drought conditions in spite of a lack of beneficial rains.”
Nielson-Gammon warns, however, that Texas temperatures have been increasing over recent decades, which contributes to evaporation and soil dryness and other factors that exacerbate drought.
“It’s going to be a wait-and-see summer regardless the forecast because of all the variables. We can offer our best forecast based upon the scientific evidence we collect, but in the end it’s anyone’s guess what will develop,” Mace added.