A summer forecast you’ve been waiting on for years

Lake Travis (Mark Batchelder/KXAN)

AUSTIN (KXAN) — Brutal summers and a never-ending drought have been part of our vocabulary in Central Texas since the summer of 2007. A child who was born here in 2008 has lived through six of the hottest seven summers, and the most intense drought ever recorded in Austin since record keeping began in 1854.

And if you were here in 2011, you can’t forget the scorching summer: 90 days where it was 100 degrees or hotter. The average high in August was 105 degrees! Almost every heat record was shattered.

But there is reason to believe this summer will be the “solar” opposite. Heavy spring rains, our first El Niño in 5 years, and several climate model simulations all suggest a long-awaited reprieve is on the way.

For those reasons–for the first time in 8 years, we are forecasting a cooler-than-normal summer. Make no mistake–there will be oppressive heat at times–but it shouldn’t be as unbearable as recent years. And it gets better–with a wetter than normal summer forecast too, it’s possible, like in 2007, we might actually have some soaking summer rain.

And there is still more evidence that something unusual is a real possibility this summer and fall. New climate simulations say the Pacific Ocean may be getting so warm, the current El Niño pattern could become the strongest since 1997. What happened that summer? Historic June floods in the Hill Country-causing the 3rd worst flood ever on Lake Travis. The lake was about 70 feet higher than it is today.

2007 COMPARED TO 2011*

  • 2007: 67.8 degrees
  • 2011: 73.5 degrees

*Average high temperature from January to April

CAMP MABRY TEMPERATURES

  • 2007: The only year to have June, July, and August’s average high temperatures all below average.
  • 2007: Lowest number of 90 degree days from June through August since 2005
  • 2007: Lowest number of 100 degree days from June through August since 2005
  • 2007: Highest number of days with measurable Summer rain since 2005
  • 2011: Tied for highest number of 90 degree days from June through August
  • 2011: Highest number of 100 degree days from June through August
  • 2011: Driest summer in recorded history.

2007: The year without a summer

This year’s summer forecast has striking resemblances to the summer of 2007, which was nicknamed “the year without a summer.” Eight years ago in late June, 19 inches of rain fell in just six hours into Lake Marble Falls. An avalanche of water triggered deadly flooding in the HIll Country, even flooding Lake Travis. That unprecedented night is what many remember, but there was something else that made the summer of ’07 unforgettable.

For 51 days in a row, summer temperatures were below normal. The high didn’t hit 95 degrees until August 1 and there wasn’t even a single 100 degree day that summer at Austin-Bergstrom International Airport. There were only three 100 degree days at Camp Mabry that summer. How did that happen? A lot of rain. By the first day of summer, 31 inches had already fallen at ABIA and rain fell in Central Texas 38 of the next 42 days.

Here in 2015, we’re noticing some similarities. El Nino patterns from both then and now are similar in strength and structure. We’re also seeing similar rainfall and temperature patterns. The number of days with measurable rain are almost exactly the same. The average high temperatures from January to April this year: 67.9 degrees in 2007; 67.8 degrees this year.

While it is unlikely we’ll see a magnitude of rain similar to the Marble Falls deluge eight years ago, if we even come close to Camp Mabry’s 18 inches of total rainfall from that summer, this one will be memorable too.

Lake levels

The Highland Lakes, specifically Lake Travis and Lake Buchanan, are the source of water for more than 1,000,000 Central Texans. Lake Travis has not been full in five years. In fact, May 1 of this year ranks as the third lowest in combined storage between Travis and Buchanan in the lakes’ history, which spans more than 70 years.

The Hill Country, comprised of San Saba, Lampasas, Mason, Llano, Burnet, Gillespie and Blanco counties is still in moderate to extreme drought category.

Highland Lakes System Profile as of May 19, 2015. (Courtesy: LCRA)
Highland Lakes System Profile as of May 19, 2015. (Courtesy: LCRA)

In order to recharge the lakes, rain must fall in the Hill Country. The most beneficial rainfall will hit one of four basins: Pecan Bayou, Lake LBJ, Lake Buchanan and Lake Travis basins. Even if water falls as far northwest as Brownwood, Texas, it could still potentially benefit Lake Travis downstream.

Thanks to the wet spring, Lake Travis is now seeing its highest levels in nearly three years; the last time Lake Travis was this high was October, 2012. Lake Travis has already increased more than 10 feet this year. Its maximum height each month jumped three feet in March and another five feet in May.

Even with the recent rainfall, lakes Travis and Buchanan are 60 percent empty together. John Hofmann with the Lower Colorado River Authority says this wet May is the best chance to downgrade the lakes’ drought in years. With continued moderate rains, the soil around the lakes stays moist. Runoff occurs more easily when the ground is saturated, which means more water drips into the lakes.

In order to completely refill Lake Travis, the lake would need an additional 218 billion more gallons of water. That’s enough to fill 327,000 Olympic size pools! Though that would be enough to lift any water restrictions, most cities would still remain in a voluntary watering conservation schedule between May 1 and September 30 of each year.

Hofmann says keeping consumers aware of how much water they’re using is key, especially with the traditionally drier months of July and August coming. “Based on what we’re seeing right now, we could go on like this a long time.” As long as water is used wisely, there’s “almost a state of stasis,” where Austin can support itself on these lower reserves.

How the aquifers are faring

The Edwards Aquifer supplies drinking water for 60,000 people in Travis and Hays counties and is another important gauge of the ongoing Texas drought. This aquifer — layers of underground rock filled with holes that can store tremendous amounts of water — is one of many around the state.

Many residents are familiar with the network of caves hidden in the woods throughout southern Travis and northern Hays counties. These pathways into the aquifer are an easy way for rain to refill the underground reservoir.

When it rains in Austin, it brings a smile to Dr. Brian Smith’s face.

“Rainfall leads to flow in the creeks which leads to recharge,” Smith said. Dr. Smith, lead scientist for the Barton Springs Edwards Aquifer Conservation District, has studied the Edwards Aquifer–feeding Barton Springs–for 14 years.

“In 2015, we’ve seen just enough rain to get us out of drought and we’re continuing to improve the situation with each little rain that we get,” Dr. Smith explained.

But other parts of the state haven’t been so lucky.

Director of the University of Texas Center for Space Research Dr. Byron Tapley designs satellites. He is in charge of the orbiting instruments that monitor how much water we have in the state, both above ground and below.

“Once we begin to go into the 2011 time frame, we begin to see it catching the entire state… major droughts, all of the wildfires,” Dr. Tapley said. “We’ve observed an ongoing reduction in the total water over the state.”

But after a wet spring, rain isn’t the problem.

“The soil is essentially dry enough that most of it is being essentially absorbed near the surface,” Dr. Tapley said. Meaning, it hasn’t been able to fill up those underground reservoirs and a lot more rain is still needed to make real progress.

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