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Irish Christmas in America Returns December 10, 2023!

Winter snow could help recharge the Colorado River. But what if it doesn't?

The Central Arizona Project canal flows through Phoenix. The city gets about 40 percent of its water from the Colorado River and its water managers must keep a close eye on snow data from the Rockies to understand local water availability.
Ted Wood / The Water Desk
The Central Arizona Project canal flows through Phoenix. The city gets about 40 percent of its water from the Colorado River and its water managers must keep a close eye on snow data from the Rockies to understand local water availability.

High in the mountains of Colorado, it’s a time of quiet.

The summer leaves have given way to bare branches, but the ski slopes haven’t yet filled with tourists—or snow. Soon, the flakes will begin to pile up, burying alpine valleys and recharging the Colorado River.

The river – which supplies water to tens of millions of people from Wyoming to Mexico – gets most of its water from high-altitude snow, two-thirds of which falls in Colorado. This winter’s forecast is unclear, but however it unfolds will have an outsized impact on the next few years of region-wide water management. Last year’s wet winter may have created more space for long-term negotiations about sharing the Colorado River, but if the region sees low snow totals in the coming months, policy analysts say things could quickly turn in the wrong direction and reintroduce some urgency to water management talks.

Navigating a wetland bramble on the banks of Homestake Creek in Eagle County, Colorado, James Dilzell, director of the nonprofit Eagle River Watershed Council, mused on the regional importance of snow in the Rockies.

“It’s amazing to think of the journey,” he said, noting that what happens to the rivers and streams near the resort town of Vail has far-reaching impacts.

The Eagle River watershed, mostly comprised of tranquil mountain creeks that surge with spring snowmelt, contributes about 3% of all the water in the Colorado River.

“Rivers are a great example of how we're all connected,” he said. “It's not a totally separate place to be here in the headwaters in Eagle County versus somewhere in Utah or Phoenix. We're all in this together, and it's all the same water.”

In just a few weeks, Eagle County’s rocky peaks won’t be the only thing covered in white. Feet of snow will soon blow into valleys and wetlands, giving water managers a clearer picture of Colorado River supplies in the seven states that use it – Colorado, Utah, Wyoming, New Mexico, Arizona, California and Nevada.

But right now, the exact amount of water coming this winter is far from clear.

‘It’s a big crapshoot’

Even in an age with complex forecasting methods and a sprawling network of weather data sensors, accurate predictions for a winter’s worth of snow are hard to come by.

“I can tell you that it's anyone's guess,” said Becky Bolinger, Colorado’s assistant state climatologist. “At the very beginning of the water year, it's a big crapshoot. We don't have a lot to go on.”

Winter weather in the Colorado River Basin this year will be largely dictated by El Niño – a phenomenon where warmer-than-usual water in the Pacific Ocean changes temperature and precipitation patterns over the Western U.S.

Typically, El Niño brings warmer, drier weather to northern parts of the West, and cooler, wetter weather to southern parts. Frustratingly for forecasters in the Colorado River Basin, the dividing line between those weather patterns falls in and around Colorado.

The latest three-month forecast released by the National Weather Service’s Climate Prediction Center shows little certainty for November, December and January. The entire Colorado River Basin appears equally likely to have above average precipitation, below average precipitation or near average precipitation.

The center’s forecast for January, February and March of 2024 predicts slightly above-average precipitation for most of the Rocky Mountains. Accurate forecasts for the amount of water that ends up in reservoirs begin to come into focus around January, though decisive data isn’t typically available until late May or early June, when streamflows reach their peak.

Forecasters do know at least one thing for certain: the sizeable precipitation last winter left an impact. Last year’s snow totals broke records in Colorado, soaking the ground with snowmelt and setting up good conditions for runoff in spring 2024. That's because when the ground is dry it acts like a sponge, soaking up and holding on to precipitation. A snowy winter and rainy summer like the last help fill up that sponge before the spring melt, and water can move more easily to the streams, rivers and reservoirs where people divert and collect it. So when snow falls this winter, it's less likely to get lost on its way to the river.

“Even though we're kind of at the beginning of the race,” Bolinger said, “we're not starting further back from the starting line than we should.”

Recently, as the gap between water supply and demand in the Colorado River basin has grown, soil moisture data has come under greater scrutiny. With the river overallocated, water managers are looking for increasingly granular, precise data about water availability.

Watching snow from the desert

Data about snow, soil and streamflow is important far from the mountains.

Take Phoenix, for example. The nation’s fifth-largest city —which gets 40% of its water supply from the Colorado River — is hundreds of miles away from the Rockies, but its water managers track Colorado weather data closely.

“We watch it throughout the winter,” said Cynthia Campbell, a water advisor for the City of Phoenix. “October 1 comes around and it's game on. We watch the snow patterns, we cheer when there's big snowfall in the Rockies.”

Water managers in other major cities like Los Angeles, San Diego, Las Vegas and Albuquerque also keep a close eye on that faraway snow and the impact it has on the nation’s two largest reservoirs, Lake Powell and Lake Mead.

Powell’s levels are largely dependent on precipitation from the past few winters. Lately, they’ve dropped to record lows, imperiling a major dam and hydropower system.

Levels in Lake Mead, which stores water for use in Phoenix and other Southwestern cities, have also hit record lows after more than two decades of drought and steady demand. With both major reservoirs on the brink, the outcome of each individual winter has become more important.

“We have, even over the past decade or two, really seen how this system can seemingly turn on a dime,” Campbell said. “Especially when it's at lower levels.”

‘We can’t be naive’

For the past few years, water managers throughout the Southwest have been operating in a kind of emergency mode. Low levels in Powell and Mead forced them to assemble a patchwork of temporary conservation deals to keep water in the reservoirs and stave off damage to major dams.

But even under intense federal pressure, the seven states that negotiate Colorado River water use have not been able to agree on more permanent guidelines that would substantially cut back on demand. Colorado River experts have framed last winter’s boost as lifting some weight off negotiators’ shoulders, finally enabling them to focus on the long term.

Arizona, California and Nevada have also pointed to a recent short-term conservation deal as a means of creating space for long-term talks, but policy analysts say a wet 2023 has done most of the heavy lifting. Talks are underway to shape a new set of guidelines for how the river is shared before the current rules expire in 2026.

Kyle Roerink, director of the nonprofit Great Basin Water Network, said last year’s wet winter could give states the space to focus on those difficult talks, but the perilous state of Lakes Powell and Mead mean subpar winter conditions could demand new short-term conservation over the course of the next few years.

“Two or three dry years will bring us back to the brink,” he said. “There's no doubt about it. So we can't be naive. We can't take our foot off the gas.”

The seven states that send delegates to those talks face an uphill battle to agree on new guidelines that work for everyone, including the 30 federally-recognized tribes that use the river’s water and have called for greater representation in shaping its future. Big cities, farm districts, conservationists, the federal government and recreators are also all advocating for water-sharing policies that protect their interests.

At the center of water management talks is the need to reduce demand on the Colorado River so it is in line with the reality that climate change is steadily reducing supply. Roerink said that will take forward thinking.

“I am just hoping, praying, crossing my fingers that decision makers on the inside this time will not take the easy route,” he said. “They're going to do the hard work, and we're going to have better long-term outcomes to avoid being where we were the past couple of years.”

This story is part of ongoing coverage of the Colorado River, produced by KUNC and supported by the Walton Family Foundation.