Texas turns drought-ending hopes to El Niño

AUSTIN (KXAN) – Lake Travis is currently less than a dozen feet from its all-time low. But remember not too long ago when it was completely full?

As recently as 2010, lake levels were more than 50 feet higher than they are now.

But beginning shortly thereafter, drought conditions settled into Central Texas and have refused to loosen their grip. In addition to low reservoir levels, some parts of the Hill Country are now in the most severe category of soil moisture drought – “exceptional” – for the first time since February 2012.

But there could be relief on the way in the coming months courtesy of a cycle in the Pacific Ocean dubbed the El Niño Southern Oscillation (ENSO) – more commonly shortened to “El Niño”.

In 1957, Texas’ worst drought ever, also known as the drought of record, came to an end.

“We had torrential rains in every sector of Texas for some two weeks,” George Bomar, author of the book “Texas Weather”, said. “We measured rainfall in feet and not inches.”

El Niño is characterized by unusually warm temperatures and La Niña by unusually cool temperatures in the equatorial Pacific.
El Niño is characterized by unusually warm temperatures and La Niña by unusually cool temperatures in the equatorial Pacific. (NOAA)

That rain was brought by an El Niño event.

Dr. Kerry Cook researches climate variability at the University of Texas. A great deal of climate variability comes from annual or decadal cycles in our oceans, such as El Niño.

Water in the Pacific Ocean is typically warmer in western regions of the basin and cooler in the east. This is due to prevailing wind patterns which cause “upwelling” – cold, deep water rising to the surface – in eastern portions, such as the coasts of Peru and Ecuador.

“On average every five years, the warm water comes back across the Equatorial Pacific from the west to the east and warms up the water over in the Eastern Pacific,” Dr. Cook said. “And that’s what we call an El Niño event.”

Here in Central Texas, El Niño years typically bring more rain and lots of it.

El Niño events have brought some of Austin’s wettest years and worst floods in our history. If those worst floods were to happen today, the water would rise up from Lady Bird Lake and cover all of what is now the Hike and Bike Trail.

In fact, in Austin’s history, two different floods have come all the way up to a stone high water marker on the side of Cesar Chavez near Colorado Street. At that intersection, Austin’s old fire tower had flood waters inside of it. If that were to happen again today, water could flood parts of Downtown Austin.

“Another sad day for central Texas.”— Dr. Glen Couchman, Chief Medical Officer Baylor Scott and White Health

“A mild El Niño can bring relief,” Bomar said, “but a moderate to intense El Niño will cause some floods.”

Back in 1997, during the last strong El Niño event, the Austin area got too much rain in too little time, leading to flooding all along the Highland Lakes and in Austin itself.

Since record-keeping began in 1950, the 1997 El Niño was the strongest event so far.

“We are now observing the strongest heat anomaly in the upper-ocean in 35 years,” Dr. Cook said.

That means this year’s could be the strongest El Niño yet.

“Models are predicting about a 70 percent probability of it happening,” Dr. Cook said. “I think those numbers are going to firm up quite a bit over the next month.”

If it does happen, we could be well on our way to making our current drought a thing of the past.

“The El Niño that seems to be forming is our best chance of breaking it in the near future,” Dr. Nielsen-Gammon, State Climatologist for Texas, said.

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