Longer fire seasons and poor snow conditions at ski resorts — those kinds of ecological and economic challenges could become far more common as the result of consecutive low snow years in the next 80 years.
A University of Idaho-led study published earlier this month in the journal Geophysical Research Letters included those conclusions.
“Across the West, we’re generally losing a lot of our snowpack — in many places, low snow conditions will be increasingly consistent from year to year,” Adrienne Marshall, the study’s lead author, said in a university news release. “Every time we have a snow drought, we’re delving into our water resources and the ecosystem’s resources. We’re drawing down on our savings without restocking the bank.”
Marshall is a postdoctoral researcher in U of I’s College of Natural Resources. U of I climatologist John Abatzoglou and hydrologist Timothy Link, along with University of California Berkeley’s Christopher Tennant, co-authored the paper.
Prior research shows warming temperatures linked to climate change will generally reduce snowpack and lead to earlier snowmelt in the West, but the year-to-year variability of snowpack had not been well established, the release said. Back-to-back low snow years could become six times more common across the West over the latter half of this century, the study found.
“The average frequency of consecutive snow drought years ... is projected to increase from 6.6 percent to 42.2 percent of years,” the report said.
The research team analyzed projected changes in the year-to-year variability of peak snowpack and the timing of peak snowpack using historical conditions from 1970-1999 and projected snowpack for 2050-2079, the report said. The 2050-2079 snowpack projections were made under a high-carbon emissions future climate scenario adopted by the Intergovernmental Panel on Climate Change. In the high-carbon emissions scenario, emissions rise throughout the rest of century, the report said.
The study’s authors defined snow drought as low snowpack conditions that historically occurred one out of every four years. These changes were greatest in Sierra Nevada and Cascades and the lower elevations of the northern Rockies, the release said.
“Throughout the Inland Northwest including northern and central Idaho, we expect to see a real increase in consecutive snow droughts,” Marshall said in the release. “The droughts will likely occur in the lower elevation ranges that historically received a decent amount of snow that is now falling as rain.”
The study also projects yearly peak snowpack will occur earlier and across a broader range of months. Historically, snowpack peaked in April but projections for 2050-79 predict more peak snowpacks in March or earlier.
Such changes will have an adverse effect on winter recreation.
“Recreational activities, such as ski resort operations, which depend on a minimum amount and relatively early snowpack accumulation as well as reliability of snow conditions coinciding with peak visitation periods, will likely be affected by altered interannual variability,” the report said.
The increased frequency of consecutive low snowpack years also will affect water resources.
“Current flood operations are guided by static rule curves that require reservoir drawdowns during fall months and neglect antecedent moisture conditions beyond the current season,” the report said. “The combination of required drawdowns and the potential for multiyear snow drought is a widespread threat to water availability from managed reservoirs.”