Shaw: Water towers on the roof of the Rocky Mountains
It’s almost March, which means we’re only just past the half way point of ski season, yet spring is right around the corner. With longer days comes deeper snowpack, typically peaking in mid-April. About the time we’re ready for winter to end, the snow piles high on our patio furniture, crushing our daffodils, and sending a clear message that Mother Nature is the boss.
For the land above the trees, snow is a lifeline in an otherwise inhospitable environment. It’s the hose that never turns off, perpetually replenishing the high mountain “water towers,” those snowfields and alpine glaciers that melt slowly throughout the year, saturating the boggy peat surrounding lakes, and filling rivers and streams to the brim with water destined for downstream users.
Or, that’s the way winter used to be in the mountains of Colorado.
In fact, a 2018 study suggests that between 1982 and 2016, snowpack declined by 41 percent over 13 percent of Western land area — mainly in the Colorado River Basin mountain ranges. It’s a statistical decline with real-time results.
When fall lasts longer, and summer starts earlier, there is simply less time for winter to settle in to the mountains. A decline of this magnitude is equivalent to losing 7.17 million square acre-feet of water, which is enough to supply drinking water to the cities of Tucson and Phoenix for four years. More recently, a study by climate scientists at the University of California, Los Angeles, suggests that 2000-21 is the driest period in 1,200 years. The major cause, according to the study, is rising temperatures.
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What does that amount of loss mean for alpine habitat? At the Rocky Mountain Biological Lab in Gothic, Colorado, Professor David Inouye, Professor Emeritus at the University of Maryland, has been recording plant and animal activity on a daily basis for over 50 years. His five decades of data is sobering: high mountain ecosystems are in peril, and the change is obvious, even to the naked eye.
High alpine ecosystems, those environments where trees can’t survive because it’s just too cold, too windy, and generally inhospitable, are changing. Warmer temperatures and less snowpack are altering that invisible line above which trees aren’t supposed to grow.
The result? Previously open, high alpine meadows are slowly filling up with trees. And those alpine plants? They’re moving into areas previously occupied by glaciers. Moving to higher ground continues to be an option, until there’s simply no higher ground to move to.
While shrinking glaciers may open new land for colonization by alpine species, there’s a bigger problem. The water tower is slowly but surely losing its ability to retain enough water to sustain life downstream.
Less snow and earlier springs may be a blessing for those of us who tire of winter around the first of February, but for the tiny plants and animals who call the alpine home, it’s a complete disruption. Instead of settling in under a wooly and protective blanket of snow for months at a time, they’re shivering under a thin cotton coverlet of wind-blown ice, their leaves tinged with frost, their roots dry and desiccated, their systems completely confused by constant temperature fluctuations and unreliable moisture.
Flowering and seed production is now a scientific crapshoot, the timing sporadic and the results highly variable. Alpine conservation scientists documenting and collecting seed for restoration work, such as Betty Ford Alpine Gardens in Vail, may find sites to be less predictable and productive as a result. Everything from bumblebees and butterflies, to hummingbirds and pikas, are affected by these changes.
For example, glacier lilies, those graceful beauties that emerge in snowbank communities and aspen groves in May, are blooming almost three weeks earlier now than in 1970, a phenomenon that affects migrating hummingbirds, says Inouye. By the time the hummingbirds arrive, many of the plants are done blooming.
In another study, Inouye monitored the bloom cycle of mountain daisies, determining that earlier spring snow melt led to earlier blooming, leaving the plants vulnerable to frost and effecting the nectar that is particularly desirable to a species of butterfly that feeds on it during egg-laying season.
Admittedly, these changes are small, but taken incrementally, they add up to an alpine environment that could look very different from what we see today. For humans, it could be devastating: about 80% of the water for agriculture, industry and drinking comes from high-elevation snowpack in the American West.
For realtime information about our snowpack, either locally or nationally, check out Snoflo.org, a website that tracks hydrology patterns across North America. You’ll find out everything you need to know about daily snow reports as well as historical data about snowpack, snow water equivalent, and temperature fluctuations.
This is the second column in a series about Betty Ford Alpine Gardens, globally recognized for its alpine horticulture, education and conservation. Located in Ford Park, Betty Ford Alpine Gardens is the highest elevation botanical garden in North America. Sarah Chase Shaw is the author of “On the Roof of the Rocky Mountains: the Botanical Legacy of Betty Ford Alpine Gardens.” Find it at Alpine Treasures Gift Shop in Vail Village or BettyFordAlpineGardens.org.