Possible easing La Niña and late spring rains could dampen drought
Brazos River, photo submitted by Shaun Holloway
As this past winter has proven, Texas weather can unpredictable, extreme and confusing.
It was anticipated that the beginning of 2021 would continue to have above-normal temperatures
and below-normal precipitation through late winter and early spring. That trend may have been
the case for most of early 2021, but a week in February took a sharp turn and became one of the
most significant weather disasters in Texas' history.
Snow- and ice-covered roads and homes, temperatures across the state hit record lows, millions of
people were left without power and water. After a week of unprecedented winter weather in the Lone
Star State, temperatures returned to the 50s and 60s the very next week.
But how did all of this happen?
"It started with some cold air sitting over the Arctic in early February," said John Nielsen-Gammon,
the state's climatologist and professor at Texas A & M University. "Eventually, the weather pattern
set up, so that cold air was continuously being drawn southward from Canada for a couple of weeks.”
Then, Nielsen-Gammon said that the last straw that created this winter storm was a weather disturbance
that was strong enough to dislodge and drive the cold air from Canada all the way into Texas.
After February's winter rollercoaster, March weather was relatively stress-free, but the month did not
bring the rain needed to relieve the state's drought conditions. In fact, even after February's snow
event, precipitation levels mostly remained below normal for most of the Brazos River basin.
According to the National Weather Service West Gulf River Forecast Center, precipitation has been below
normal over most of the WGRFC region during the winter months. Only areas across Northeast Texas, the
Texas Panhandle, South Central Texas and a small portion of Southwest Texas experienced above-normal
precipitation during the winter season.
Looking forward into spring and summer, the consistent trend of above-average temperatures with below-average
precipitation is expected over all of Texas. Warmer temperatures and low precipitation levels will likely
cause drought conditions to worsen and expand.
"Precipitation, temperature and drought condition forecasts all suggest an expansion and intensification
of drought conditions are likely over the next three months," the NIDIS said in a recent
As of April 9, 2021, about 91.5% of Texas was experiencing abnormally dry conditions, 74.5% of Texas was
experiencing moderate drought, 38.5% of Texas was experiencing severe drought, 23.6% of Texas was
experiencing extreme drought, and 8.5% of Texas was experiencing exceptional drought. 100% of the
Brazos River basin experienced some sort of drought status as of that date.
Drought can have a severe impact on agriculture, recreational activities, water supply and more. If drought
conditions continue to worsen, many aspects of Texans' daily lives will be altered. When severe drought
conditions form, pasture conditions become poor, crop yields decrease, and wildlife moves into populated
areas. At drought's worst stage, exceptional drought, the seafood, forestry, tourism and agriculture
sectors report financial losses, water levels drop significantly, and water quality suffers.
However, Nielsen-Gammon says it's too early to be pessimistic about late spring rains that could relieve the
state's drought conditions.
The upcoming months of May and June are typically the wettest months of the year, and even with the possibility
of below-normal precipitation levels, there is a good chance that the Brazos River basin will experience
The El Niño-Southern Oscillation (ENSO), the recurrent weather patterns in the central and eastern tropical Pacific
that often influence whether Texas will enjoy heavy rainfall or prolonged drought conditions, is currently still
in a La Niña status. A La Niña forms when waters in the tropical Pacific Ocean are much cooler than normal, which
typically results in warmer and drier weather for Texas.
However, the La Niña weakened through February and March, according to climate.gov.
predicts a transition to ENSO-neutral conditions by the end of spring, although there is a chance that conditions
may revert to La Niña later in 2021. ENSO-neutral conditions mean that Texas' weather could tip in either direction.
"As we get into spring, the influence of La Niña weakens, so the weather patterns will stop favoring below-normal
rainfall. At the same time, it looks like La Niña will be weakening too," Nielsen-Gammon said. "This basically
means that we have no clue what's going to happen to rainfall in Texas from May onward. The dry soils in many
areas will inhibit the development of thunderstorms while also making it harder for heavy rain to produce flash
flooding. During April and May, in particular, weather systems are strong enough to generate their own rainfall,
no matter what's happening on the ground."
Aaron Abel, the Water Services Manager at the Brazos River Authority, said in the recent virtual public meeting
that regardless of the continuation of drought conditions and lack of significant rainfall, the BRA's Water
Supply System stays in good shape heading into late spring and early summer.
As of April 7, the BRA system is 97% full and storing about 1.87 million acre-feet of water. Lake Georgetown and
Lake Somerville remain under Stage 1 Drought Watch, which are in place to raise customer and public awareness
of drought conditions.
"We’re in a good position right now,” Abel said. “Everyone is hoping for some rain, and I think we’ll get it.”
The above-normal temperatures will persist for the foreseeable future due to the long-term warming trend. In fact,
Nielsen-Gammon said that due to this persistent warming trend, the definition of “normal” temperatures will no
longer be based on average conditions in 1981-2010 and instead be updated to average conditions in 1991-2020.
“Since the last decade was warmer than temperatures in the 1980s, the new normal will be warmer too,” Nielsen-Gammon
The combination of warmer temperatures, statewide drought conditions and lingering La Niña conditions could lead
to an early, intense wildfire season. A bad wildfire season requires wet conditions followed by dry conditions.
The other thing you need is a day of bad fire weather—strong winds with very low humidity.
“Until the rains come and the grasses green-up, every dry and windy day means a risk of fires starting and rapidly
spreading. So far, areas from I-35 southeast have greened up nicely, but northwest of there, the wildfire risk is
still present,” Nielsen-Gammon said.
You can stay up to date with rainfall, streamflow and reservoir elevation data within the Brazos River basin by
clicking here. For helpful resources about dealing
with drought, click here.