MISSOULA — This winter is off to a slow start and researchers are warning today's "unusual" could become "normal" — and even more severe in decades to come.
A new study from the Berkeley National Laboratory suggests our recent "hit or miss" winters are actually part of a larger trend, with mountain snowpack dropping since 1950, and no longer consistent on the "April 1st" data we've used to measure water runoff.
"Some of our results of the study really point to a similar magnitude of loss by mid-century on the order of 20% and up to as high as 50% by end of the century," noted Berkeley National Laboratory research scientist Dr. Erica Siirla-Woodburn.
"But we're finding that as the world warms about a degree Celsius since preindustrial times across the western US, that that peak timing of April 1st is actually moved shifted earlier in time by about a week," added Berkeley National Laboratory research scientist Alan Rhoades. "And so what we sought to do is to reassess that April 1st assumption."
Rhodes, Sirrila-Woodburn, and their colleagues see a future where snowfall could actually become a rarity, starting in the coast ranges and spreading our way by the 2070s.
"And so we coined this term low to no snow. By using this, a peak snow water equivalent metric combined with a percentile approach, and we used these percentiles because we didn't want the magnitude, we didn't want to set a threshold of what a magnitude should look like to be normal or not normal and be applicable across different regions," Rhodes said.
"Spring snowpack is very important for tree species in the High Sierra, the High Rockies, et cetera, and also is very important in maintaining soil moisture contents throughout the spring and summer season, which is very important for wildfire potential and whatnot. And then there's you know, endemic species that are also dependent on spring snowmelt pulses into creeks and rivers." - Berkeley National Laboratory research scientist Alan Rhoades
"Climate change impacts in the mountains are not an isolated kind of problem, just for those communities. That water is distributed hundreds, even thousands of miles away," Sirrila-Woodburn told MTN News. "There's a lot of energy costs and financial costs associated with that. And so you know what's going on in terms of snowpack really has this outsized impact in places other than just, you know, a specific mountain range."
The report suggests the problem is more far-reaching than just ski areas shutting down.
"Trying to understand this the amount of snowpack decrease in the future is not really the end all be all of the story. There's this whole other cascading set of impacts that happen once the snowpack melts in terms of the hydrology." - Berkeley National Laboratory research scientist Dr. Erica Siirla-Woodburn
What the report forecasts is a cascading effect, with less water meaning drier soils, sifting plant and animal species, and more fire; not less moisture necessarily — but rain instead of snow.
"And that's just simply due to the fact that the freezing point of water is non-negotiable and that, you know, as you as the world continues to warm by a degree 2º, 3°, 4° into the end of the century that freezing line, especially at lower elevation, shifts upslope or it can't be persistent for long periods of time," Rhodes explained. "So that just inhibits, even if you have same precipitation amounts, you just can't have snowpack accumulate and build and be maintained throughout the year."
There are going to have differences in years from one to the other but researchers are looking at this picture over decades.
"That's right, and that's where that's where we really don't have that historical analog, and so I think that's where looking to try to understand what's the implications of prolonged periods of drought What does it mean for sort of thresholds in our water system, that sort of results in a quote, unquote, water failure," Sirrila-Woodburn said.