Water Wisdom: Shrinking snowpack

By Stephanie Lynn EBS Contributor

Despite the recent subzero cold snap, Montana, on average, is heating up as a result of human-induced climate change.

The uptick in greenhouse gases in the atmosphere since the Industrial Revolution has caused a rapid rise in temperatures globally, triggering impacts to both humans and natural systems. The consequences are already apparent in Montana, where the climate may warm faster than the rest of the United States, according to the 2017 Montana Climate Assessment. The study reported statewide temperatures increased 2-3 degrees Fahrenheit between 1950 and 2015, and predicted a continued rise in temperatures by an additional 4-6 degrees by mid-century.

Even small shifts in temperature can lead to big impacts on snowpack and water supply. A few degrees of increase could result in an additional month or longer with temperatures above freezing in western Montana. As a result, more precipitation will fall as rain rather than snow.  

“That rain doesn’t hang around into the springtime, so it is more likely lost from the system rather than melting out in the spring or summertime when people, fish and wildlife need it most,” said Molly Cross, climate change adaptation coordinator for the Wildlife Conservation Society.

Snowpack has decreased by approximately 20 percent statewide over the past 80 years, as reported by the Montana Climate Assessment. As average temperatures warm, this trend may continue over the next century, particularly when conditions hover near freezing in the spring and at mid and low elevations.

Deteriorating snowpack imperils the state’s outdoor economy, particularly winter recreation. One national study published by the peer-reviewed journal “Global Environmental Change” forecasts that warmer winters will reduce ski season length at some downhill resorts by more than 50 percent by 2050. Although elevation and northern latitude position Big Sky for climate-change resilience, the ski season may be as much as a month shorter by mid-century, the study predicts.

According to Twila Moon, a Big Sky-based glacial research scientist, reduced snowpack also influences water supply, fisheries, wildfire risk and agriculture.

“We need to plan for these changes and also act individually, locally and regionally to reduce our fossil fuel use so that we can help to slow or reduce the changes,” Moon said. “That is the best protection for ensuring that the economy and activities we establish today will be strong in the future.”

Proactive management strategies, such as those outlined in the Big Sky Sustainable Watershed plan that recharge both groundwater levels and summer streamflow, will help the community adapt to both shrinking snowpack and warming temperatures.

Stephanie Lynn is the education and communications coordinator for the Gallatin River Task Force.