The Arizona Republic
Drought expected to continue in Arizona
Drought will continue into the spring months across Arizona, increasing wildfire risk and stress on water resources and agriculture, according to a new forecast by the National Oceanic and Atmospheric Administration.
The projected level of drought means there will likely be a below-average snowpack in the mountains, drier than normal soil moisture and a lack of
“More than likely, we’re going to be continuing these drought levels … it will definitely take more than one season, more than one wet year, to move out of drought.” Erinanne Saffell Arizona climatologist
water availability in places, according to Brad Pugh, a meteorologist with the Climate Prediction Center at NOAA.
Arizona has experienced a long-term drought dating back to 1996, which was exacerbated by a dry monsoon season in 2020, when the state received little rain in July, August and September.
It was worsened by two La Niña winters in a row, several climatologists and meteorologists said. During La Niña cycles, colder than normal sea surface temperatures in the eastern equatorial Pacific typically produce drier winters in Arizona.
While Arizona recorded the second wettest July on record last summer, it wasn’t enough to make up for the winter deficits.
La Niña and El Niño — the opposite phenomenon, where warmer temperatures in the eastern equatorial Pacific tend to cause wetter winters in Arizona — are naturally occurring phenomena. But some scientists believe they may become more intense or frequent or both as a result of climate change, although the connection is not clear.
“The drought expansion and intensification that we’ve had across the country this past winter is largely due to La Niña,” Pugh said. “And the drought we’re seeing in the western U.S. is consistent with what we would expect in a warming climate.”
In Arizona, moderate and severe drought levels are increasing, with areas of extreme drought on the west side of the state, according to state climatologist Erinanne Saffell. Abnormally dry conditions, one level below what’s considered drought, have decreased in parts of central Arizona, she said.
Saffell noted that extreme drought levels fell this year compared with last year, with last year’s extreme drought at 85% of the state and this year’s at 6%.
“It’s not unexpected to see that the spring outlook is to continue drought, and perhaps even extend some of the drought,” she said. “More than likely, we’re going to be continuing these drought levels … it will definitely take more than one season, more than one wet year, to move out of drought.”
In-state reservoirs remain stable
About 75% of Arizona is in drought right now, ranging from moderate, severe, extreme and exceptional levels, a decrease from last year when nearly 100% of the state experienced drought, according to statistics from the U.S. Drought Monitor.
The state has suffered increasing drought in the past few years: In March 2019, about 5% of the state experienced drought. In 2021, after little rain during monsoon season, the number surged, with nearly 100% of the state experiencing drought.
Bo Svoma, a meteorologist for Salt River Project, which provides water to about half of metro Phoenix and draws from the Salt and Verde rivers, said NOAA’s spring forecast of drought won’t significantly affect the utility’s reservoir operations.
Svoma said unlike the Colorado River system, SRP’s reservoir levels haven’t changed much since Arizona’s 26-year drought began. The reservoir is currently at 72% capacity. In May 1995, it was at 75% capacity.
“This drought is thought to be the worst in the last 700 years and SRP storage is pretty much the same now as it was at the beginning of the drought,” he said. “And that is certainly not the case for the Colorado River reservoir system, which has steadily gone down through that severe drought.”
Lake Mead, the largest reservoir on the Colorado, is currently about 34% full. Lake Powell, the other major reservoir on the river, is hovering around 24% of capacity.
Droughts are ‘complicated’
Svoma attributes this to a few factors. First, SRP’s system is smaller than the Colorado River system. It’s able to refill in one wet winter, which the state saw in 2017, 2019 and 2020.
Second, the utility’s system is in long-term balance, with demand even slightly decreasing from more efficient water use, while the Colorado River system is over-allocated, meaning that more water is taken out of the system than comes in on average.
And, according to research over the past decade, the Salt and Verde rivers are less sensitive to warming than the Colorado River, which was declared in shortage for the first time ever last August. Aside from less rainfall, hotter temperatures take a big bite out of the runoff budget because of increased evaporation, Svoma said.
The Colorado River basin receives its runoff in the warmer months of April, May and June from a melting snowpack, when the days are long and the sun is high in the sky, while the Salt and Verde rivers receive their runoff from rainfall and snowmelt in the cooler winter months of January, February and March.
Still, Svoma expects the reservoirs to be 10% to 15% lower than current levels by the end of summer because of this year’s dry winter. He notes that’s when the utility has the highest demand for water, although he isn’t worried about the reservoir getting to an uncomfortably low level.
“It’s important to look at drought through where you get your water from,” Svoma said. “So if you get your water from the Colorado River, then your drought’s tied to storage in Lake Mead and Lake Powell, which is a multi-decade thing, bleak to climate change. If you get your water from Salt River Project, then this last dry winter is not really having a big impact. If you get your water from wells, then maybe you got to think a little harder about how a single wet winter impacts your water situation.
“So the drought issue is complicated, and I think looking at those drought maps, you have to be a little thoughtful on how you interpret those.”
Zayna Syed is an environmental reporter for The Arizona Republic/azcentral. Follow her reporting on Twitter at @zaynasyed_ and send tips or other information about stories to email@example.com.
Environmental coverage on azcentral.com and in The Arizona Republic is supported by a grant from the Nina Mason Pulliam Charitable Trust. Follow The Republic environmental reporting team at environment.azcentral.com and @azcenvironment on Facebook, Twitter and Instagram.