The hot dry conditions that melted strong snowpack early in 2020 and led to severe drought, low river flows and record setting wildfires across the state could be a harbinger of what is to come in Colorado.
Climate change is likely to drive “chaotic weather” and greater extremes with hotter droughts and bigger snowstorms that will be harder to predict, said Kenneth Williams, environmental remediation and water resources program lead at Lawrence Berkeley National Laboratory, headquartered in California.
“We are looking to be moving toward a future that is really decoupled from the past,” said Williams, who is leading a long-term watershed research project in Crested Butte.
In 2020, the Colorado River system had 100% of average snowpack on April 1 but then thwarted expectations when it didn't deliver the 90% to 110% of average runoff that water managers could typically predict. The river system only saw 52% of average runoff because water was soaked up by dry soils and evaporated during a dry, warm spring, said Brad Udall, senior water and climate research scientist at Colorado State University.
“It’s not typical, but it could very well be our future,” he said.
The 2020 drought will end at some point, but that appears unlikely this spring with the National Oceanic and Atmospheric Administration forecasting above-normal temperatures and below-normal precipitation through March, April and May.
Conditions could improve more rapidly on the eastern plains with big spring and summer rain, said Russ Schumacher, Colorado's state climatologist.
In the larger picture, breaking the drought across the vast Colorado River Basin will likely take a string of winters with much above average snowfall, Schumacher said.
In the long term, conditions across the Southwest are going to become more arid as average temperatures rise, driven by greenhouse gas emissions, Udall said, with lower soil moisture and stream flows among the negative impacts.
The 19-year stretch of only intermittingly interrupted drought from 2000 to 2018 in the Southwest U.S. was exceeded only by a late 1500s megadrought, the journal Science reported in a paper this year.
"We shouldn’t think of the last few years as record-setting warmth, but instead we should think of them as the coolest in the next 100 years," Udall said.
Complicating this impending scenario is expected Colorado population growth from about 5.8 million people to 7.9 million by 2050, according to the state demographer's office.
New reservoirs could play a role in the future, but construction alone cannot resolve the coming water woes.
"Anyone who thinks they can build themselves out of climate change is nuts," Udall said. "There is a limit to the amount of storage that’s helpful.”
Too much storage can sit empty and if the water is allowed to sit for too long a valuable portion is lost to evaporation, he said.
In the highly variable years of climate-related weather to come, keeping water flowing to homes and farms will take better planning and a much better understanding of the “water towers of the West,” the remote peaks where significant amounts of snow accumulate above 8,000 feet.
Water managers are keen to know not just how much water may flow into rivers and streams, but when, and also what it might contain because as water flows drop water quality is also likely to be more of a concern.
Understanding Colorado’s water towers
Fresh snow left the peaks near Crested Butte radiant in the cold January sunshine as research technicians Curtis Beutler and Alexander Newman augured through the frozen East River and dug down into the snow for samples. The sampling helps the team working in the watershed understand how much water is stored in the snow, how dust on the snow that can accelerate its melt, and the chemistry of the snow and water, among other research questions.
The technicians are two of the 150 researchers that have worked near Crested Butte since 2014 as part of the Department of Energy’s Watershed Function Scientific Focus Area program. The program seeks to better understand how water flows through the system so researchers can better predict how much water to expect from winter snowpack and when it will arrive downstream, among other aspects of the snow and water science that will aid water management for cities and farms. The multi-million dollar research does not have an end date, although it is formally reviewed every three years, said Williams, the project leader.
The work in Crested Butte is expected to inform water predictions across thousands of watersheds, Beutler said.
The models they are developing can accurately predict how much water is in the snow but still need to be refined to determine when that water will arrive, Williams said. The models can be weeks to a month off in terms of determining when runoff will show up, he said. Snowmelt is not just a function of temperature, it’s also affected by wind, dust on the snow, solar intensity and other factors that need to be better understood, he said.
As the climate warms, the work in the Upper Gunnison watershed is also exploring how native plants impact the system and possible depletion groundwater at high elevation. They are also studying water quality changes and earlier snowmelt, a particular problem for farmers because the runoff can hit rivers and streams before it is useful to them, Williams said. Early snowmelt can be driven by warmer temperatures, rain on snow and also dust that changes the snow surface from highly reflective to one that will more easily absorb sunlight.
“Mountain watersheds are really bellwethers of climate change," Beutler said. "They are changing faster and they are changing in different ways than other landscapes.”
Banding together for better data
The rapid change has left water managers and researchers in need of better data to understand short-term trends, such as how much runoff to expect this year and longer-term shifts.
Traditionally Colorado and the West have relied on a network of more than 800 snow telemetry sites — SNOTELS, as they are called by the Natural Resources Conservation Service — that automatically collect snowpack, temperature and precipitation. But now more snow is falling at elevations above the SNOTELS and aerial observations are needed to provide an alternative source of data on snowpack utilities and others wouldn't otherwise know about, Williams said.
Scientists working on projects in Crested Butte and water managers have started to rely on NASA-developed methods to measure the snow depth and water content from an airplane. The Airborne Snow Observatory relies in part on LIDAR, a form of remote sensing that uses pulsed laser light to gather data on the snow depths and estimate water content. The scientists on the ground in Crested Butte help confirm the accuracy of the estimates the plane takes, Williams said.
From the aerial data, Denver Water determined 150,000 acre feet of water had yet to melt in June 2019 that SNOTEL sites couldn’t detect, said Laurna Kaatz, climate science, policy, and adaptation program director for Denver Water.
“The value for Denver water was just immediately obvious,” she said.
So Denver Water is forming a new collaborative to bring utilities, including Colorado Springs Utilities and other water users, such as water conservancy districts that serve farmers and ranchers, together to fund statewide flights, which can be quite expensive, she said.
The formal planning work around what data to collect and funding flights is set to begin in April and already the collaborative has attracted members from across the state, Kaatz said.
The group hopes to start funding the flights in about a year to provide the high quality data to water managers, Kaatz said. Having that data will be a valuable asset in Colorado’s semi-arid climate as it warms, she said.
“Warming is here and now. It’s not the next generation’s challenge."
Warmer temperatures in the coming decades could lead to more rain on snow, or rain instead of snow, events that could change how water moves through the system and the mountains could see more water seeping into the ground earlier and less water making it into rivers, Kaatz said.
Understanding mountain weather
The work to understand snowpack and western watersheds in Crested Butte will get a boost in September when scientists dedicated, in part, to understanding the mechanics of mountain precipitation set up the Surface Atmosphere Integrated Field Laboratory in the area, said Daniel Feldman, the principal investigator of the project based out of the Lawrence Berkeley National Laboratory. The Department of Energy funded his team to work in the area for about two years to better understand the precipitation flowing into the Colorado River watershed that supports 40 million people, he said.
The new observatory will provide the area’s only weather radar, filling a black hole for radar data in the area and additional instrumentation to help understand why precipitation may fall on one ridge but not one nearby at the same elevation, he said.
“There are two principal ways we are thinking about this … Not just what is causing each water drop to happen, but what might be keeping that from happening in the first place,” he said.
Understanding the detailed weather mechanics will help researchers build models to help improve predictions for the entire river, he said. The team will study precipitation year-round including the monsoons, he said.
The atmospheric team will also be to provide a baseline of how much precipitation is coming into the watershed, so it can be compared to how much is flowing out, he said.
Depletion of groundwater
The rapid spring runoff is often the star in the water world. But high elevation groundwater is key to feeding streams in the late summer and winter, helping to sustain fish and late season irrigation. It is also an important source for reservoirs, said Rosemary Carroll, a hydrologist with the Desert Research Institute and collaborator on the Department of Energy projects in Crested Butte.
When Carroll started studying groundwater in the upper Gunnison watershed, she expected to find water that had percolated through the soil for two or three years before reaching streams. Instead, she’s found groundwater about a decade old, which has benefits and drawbacks during dry times, she said.
If the watershed is in a shorter drought, the groundwater can act as a buffer supplying old water that fell as snow and rain years ago, she said. But if it is a sustained drought then the absence of water from the system persists through a lack of groundwater, she said.
If the area continues to see hotter drier conditions, it’s likely that groundwater coming to the surface would be older and there will be less groundwater available to support streams, she said.
“You start depleting your stores everywhere,” she said.
As that happens downstream irrigators could have to rely more on pumping their local groundwater, she said.
At the same time, water is getting sucked up by the atmosphere and plants in hotter weather, lowering stream flows and reservoir levels. For farmers and ranchers, hot dry conditions can drive the need to water more or plant less, Carroll said.
“Ranchers and irrigators — they are not unaware that these changes are happening … There is a lot of anxiety,” she said.
As flows drop, water quality also becomes more of concern because there is less water to dilute existing contaminates.
In Crested Butte, the samples Beutler and Newman take from snow pits, the East River and other areas help researchers to better understand some of potential pollutants and other chemicals in the water. The work also helps trace how water moves through the system because when snow falls it is very pure, but picks up nutrients as it moves through soil and rock, Williams said.
“During the melt season we experience what’s called an ionic pulse, which is when all of those chemical constituents and nutrients, maybe even harmful elements get flushed out of the snowpack and hit the river,” Newman said.
By sampling throughout the winter, scientists can see how those chemicals are accumulating and predict how they are going to behave, Newman said.
Preparing for the unknown
In the shadow of Gothic Mountain's near vertical rock walls, Heidi Steltzer, an environmental scientist, Fort Lewis College professor and a member of the Crested Butte team, cross-country skied in the January sunshine along a winding road through the watershed she has studied since 2015 and described the extremes she's observed across the Rockies. She has been studying alpine plants since the big snows of the 1990s and through the droughts since 2000. In 2012, she measured 1% soil moisture at 12,100 feet in the San Juan Mountains, a condition you would find in the desert.
"That summer the skypilot bloomed produced these beautiful purple flowers and they all fell off in a day," she recalled
The plants tell the story of the watershed, without the need to drill for samples everywhere. For example, the huge leaves of skunk cabbage show you that water is abundant in that area, Steltzer said. As part of her work, her team members gather highly detailed data about the plants' biomass, height, water in their leaves, and the nutrients they hold, among other characteristics and then they use a spectrometer to make a light-based fingerprint of the land surface.
"We are relating everything we can physically measure at a location to that light-based data and then the goal is to scale that up. ... The idea is: Can we look at the surface and know what’s happening below ground?" she said.
As the climate warms and the snow melts earlier, she's observing plants starting to grow at the same time at varying mountain elevations, when normally there would be gaps going up the hillsides. The similar timing in plant growth could leave more water in the system in August, as plant growth slows earlier, although that's still unknown, she said.
During her years in the field, she's noted a quality in Western Slope residents that many farmers and ranchers showed during the Dust Bowl years as they continued to plow more and more land —hope. The difference between now and then, however, may be our ability to adapt more quickly to climate changes, she said.
While our hope makes us human, big snow years should not fool us into thinking that the state is not on a long-term trend toward less snow and a higher snowline, Steltzer said, even though we look to those years as proof change isn't happening.
“The greater variability is important to recognize, but each year we get one of those more abnormal high snow, high rain, maybe somewhat cooler years … maybe we will renew our hope that years before that of drier, hotter times aren’t the new normal because we are a hopeful species,” she said.
Steltzer took her ideas and experience before Congress in January 2020, where she called for a new narrative on climate change developed with respect and good will, she said.
Even though we will never know all that's to come as the climate changes, adaptation in cities and across agriculture is already happening and it can be even more visionary, she said.
“We can plan so well that no matter what the future brings for weather, we got this. That’s the mode I want us to be in,” she said.