Is Texas deluge a sign to parched California?
El Niño linked to drenching — could affect the West too, scientists say
Several dry years left water supplies short and farmland buried in dust. Some called it the worst drought in a generation.
That was Texas just weeks ago, before a series of deadly storms dumped record amounts of rain and virtually washed away all worry about water.
Now, scientists are linking the wet spell that hit the parched southern U. S. to a strengthening El Niño, a weather pattern that is expected to stick around until California’s rainy season arrives and perhaps bring drought relief to the similarly arid West — or so they hope.
“Winter’s a long way off,” said Mike Halpert, deputy director of the U. S. Climate Prediction Center. “At this point, we’re not prepared to say that we’ll see a strong El Niño this winter ... but I like to tell people that things are evolving nicely.”
The closely watched El Niño, characterized by warm surface temperatures in the tropical Pacific Ocean, can drive moisture into the atmosphere and trigger rain around the globe. Some of California’s wettest periods have come during El Niño patterns, including the 1997- 98 rain year that brought San Francisco an unprecedented 47.2 inches of water.
The downpours in Texas,
Oklahoma and Louisiana that have flooded roads and had left 21 dead as of Thursday are at least partially fed by the El Niño that developed in late winter, Halpert said. Recent showers in Southern California and other parts of the Southwest, while sparse, may also be products of the system.
However, Halpert warned, there’s no guarantee that El Niño will work its magic next winter, when California weather conditions are most suited for rain.
The Climate Prediction Center last week pegged the odds of the current El Niño continuing through the remainder of 2015 at 80 percent, but how strong the pattern might be remains unclear.
Historically in California, El Niño patterns that have been weak or moderate have had little correlation with wetter weather, while more intense ones have been only loosely associated.
“It’s a little early in the year to get an idea of the strength of the event,” said David Unger, a meteorologist at the federal government’s Climate Prediction Center.
Last year, climate experts similarly bet on an El Niño building offshore, but that never materialized. While sea temperatures rose, the atmosphere didn’t respond by picking up moisture.
“This year looks considerably better,” Unger said.
With a handful of days left in May, Texas has already received more than 7 inches of rain for the month on average statewide, the most since recordkeeping began. Consequently, the state’s reservoirs are recharged and soils are replenished. As of Thursday, no part of the state was considered to be in a “severe” drought, according to the U. S. Drought Monitor. That’s compared with a year ago, when half the state was experiencing such conditions, and 2011, at the height of the drought, when nearly everywhere was dry.
In California, 94 percent of the state is considered to be in a severe drought.
While the state would benefit from the rains seen in the South, the severity of the situation is unenviable. Scientists say the violence of the storms probably isn’t connected to El Niño — only to local weather conditions.
Noah Diffenbaugh, an associate professor of Earth system science at Stanford University, says climate change makes such extreme local systems more likely.
“Theory predicts that the intensity of wet events should increase with global warming, and we are seeing that,” he said.
In California next winter, storms could be more severe, Diffenbaugh said. But drought conditions could be more severe, too: “With warming temperatures, both are true at the same time.”
Warmer weather has another troublesome effect on California: less snow. At least a third of the state’s water supply comes from mountain snowpack, which is particularly important because it melts into reservoirs during the dry summer months when water is scarce.
“Temperatures will make it even more difficult for this drought to break,” Diffenbaugh said.