From forecasts to faucets: How fall weather impacts our water supply

We have officially entered fall, the season when all the months end in B-E-R, and the weather can be unpredictable.

Heading deeper into fall, the reservoirs in the Brazos River Authority’s (BRA) system are more than 90 percent full. But drought conditions have been fluctuating with an upward trend each week, jumping from just 2% of the Brazos basin experiencing some form of drought in late August to more than 89% in mid-October, then dropping to 66% moving into November.

The Brazos River Basin has experienced an ENSO-neutral weather pattern since spring. A neutral pattern indicates that neither the La Niña nor El Niño weather patterns are influencing the atmosphere.

“La Niña typically brings warmer temps and drier weather for us,” says Aaron Abel, water services manager at the Brazos River Authority. “El Niño normally brings above normal rainfall and potentially cooler temperatures.” When neither pattern exists, or ENSO-neutral, the phase represents a normal state that can also signal variable and less predictable weather patterns compared to the more extreme phases of La Niña or El Niño.

According to the National Weather Service Climate Prediction Center, a shift in weather patterns might be approaching.

According to John Nielsen-Gammon, Texas State Climatologist and director of the Southern Regional Climate Center at Texas A&M University, “We have a La Niña Watch now, meaning that the formation of a La Niña in the near future is likely.”

A watch is issued when conditions are likely to develop into El Niño or La Niña within the next six months.

“A La Niña watch doesn't affect our weather,” Nielsen-Gammon said. “But the more conditions resemble a La Niña, the more likely the winter and surrounding months are to be relatively warm and dry, with an occasional burst of intense cold.“

Neilsen-Gammon adds, “If a La Niña does form, it is likely to be weak, which means that its effect on our weather would be weak as well, a slight tilting of the odds toward warm and dry. Climate change will probably have a larger effect on our wintertime temperatures than will La Niña.”

According to the World Meteorological Organization, climate change means long-term changes in the Earth’s climate. These changes can be observed in shifts to phenomena such as average temperatures or rainfall patterns and often persist for many decades or even longer.

What does all of this mean for the Brazos River Basin?

“As long as we don't have any extended very dry periods, soil moisture and reservoir levels should increase through the winter and early spring,” reports Neilson-Gammon. “Late August and September have been relatively dry, but October always brings the potential for a deluge or two.”

When it comes to increasing drought conditions within the basin, Neilson-Gammon warns that wildfire risk could increase. “A dry winter will mean that springtime plant growth will more rapidly deplete the available moisture and lead to agricultural drought impacts,” he said. “Also, since much of the summer was wet, there is enhanced wildfire risk this coming winter when things dry out and grasses become dormant.”

As long as reservoir levels continue to drop and the level of drought conditions worsen, water conservation will remain crucial. Simple actions like taking shorter showers and turning off the water while brushing your teeth may seem small, but if everyone does the same, these small steps can have a big impact.