Home Glaciers Shaw: water towers on the roof of the Rocky Mountains

Shaw: water towers on the roof of the Rocky Mountains

0
A solar pillar shines as snowflakes fall near Camp Hale in January. For the land above the trees, snow is a lifeline in an otherwise inhospitable environment.
Chris Dillmann Archive / Vail Daily

It’s almost March, which means we’ve only just passed halfway through the ski season, but spring is just around the corner. Longer days come with a thicker snowpack, usually peaking in mid-April. About the time we’re ready for winter’s end, snow is piling up on our patio furniture, crushing our daffodils and sending a clear message that Mother Nature is boss.

For the land above the trees, snow is a lifeline in an otherwise inhospitable environment. It’s the pipe that never goes out, perpetually filling the high mountain “water towers”, those alpine snowfields and glaciers that slowly melt throughout the year, saturating the swampy peat of the surrounding lakes. and filling rivers and streams to the brim with water destined for downstream. users.

Or, that’s how winter was in the mountains of Colorado.



In fact, a 2018 study suggests that between 1982 and 2016, snowpack decreased by 41% over 13% of western land area, mostly in the mountain ranges of the Colorado River Basin. It’s a statistical drop with real-time results.

When autumn lasts longer and summer starts earlier, winter simply has less time to settle in the mountains. A drop of this magnitude is equivalent to losing 7.17 million acre-square feet of water, enough to provide drinking water to the cities of Tucson and Phoenix for four years. More recently, a study by climatologists at the University of California, Los Angeles suggests that 2000-21 is the driest period in 1,200 years. The main cause, according to the study, is rising temperatures.



What does this 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 daily for more than 50 years. Its five decades of data are sobering: high mountain ecosystems are at risk and the change is evident even to the naked eye.

High mountain ecosystems, those environments where trees cannot survive because it is too cold, too windy and generally inhospitable, are changing. Warmer temperatures and less snow cover are changing that invisible line above which trees are not supposed to grow.

The result? The once open high alpine meadows are slowly filling up with trees. And those alpine plants? They move into areas previously occupied by glaciers. Moving to higher ground continues to be an option, until there is simply no higher ground to move to.

Snow falls on trees already covered in December in Vail. Less snow and earlier springs may be a blessing for those of us who grow weary of winter around February 1, but for the tiny plants and animals that inhabit the alpine home, it’s complete disruption.
Chris Dillmann Archive / Vail Daily

Although shrinking glaciers may open up new lands for colonization by alpine species, there is a bigger problem. The water tower slowly but surely loses its ability to hold enough water to sustain life downstream.

Less snow and earlier springs may be a blessing for those of us who grow weary of winter around February 1, but for the tiny plants and animals that inhabit the alpine home, it’s complete disruption. Instead of settling under a woolly, protective blanket of snow for months, they shiver under a thin cotton blanket of windblown ice, their leaves tinged with frost, their roots dry and parched, their systems utterly confused by constant temperature fluctuations and unreliable humidity.

Flowering and seed production is now a scientific game of chance, the timing sporadic and the results highly variable. Alpine conservation scientists documenting and collecting seeds for restoration work, such as Betty Ford Alpine Gardens in Vail, may find sites 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 snowdrift communities and aspen groves in May, bloom almost three weeks earlier now than in 1970, a phenomenon that affects migratory hummingbirds, Inouye says. . By the time the hummingbirds arrive, many plants have finished flowering.

In another study, Inouye monitored the flowering cycle of mountain daisies, determining that earlier spring snowmelt resulted in earlier flowering, leaving plants vulnerable to frost and affecting nectar which is particularly desirable for a species of butterfly which feeds on it during the egg-laying season.

Admittedly, these changes are small, but taken gradually, they add up to an alpine environment that could be very different from what we see today. For humans, this could be devastating: approximately 80% of the water for agriculture, industry and drinking comes from the high altitude snowpack in the American West.

For real-time information on our local or national snowpack, see Snoflo.org, a website that tracks hydrological trends in North America. You’ll find everything you need to know about daily snow reports as well as historical data on snow cover, snow water equivalent and temperature fluctuations.