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Low-to-No Snow Future in Paradise Valley

What does a low-to-no snow future look in like in Paradise Valley?


Predictions for Snowpack in the West

There is strong evidence and high confidence that anthropogenic climate change is actively decreasing the snowpack across the American West.


A group of researchers recently conducted a review of what a low-to-no-snow future would look like in the West, and what that means for valuable water resources. Two metrics for analyzing snowpack are SWE (snow water equivalent) on April 1st and the date in which peak SWE occurs. Both are useful in looking at a heterogenous mountain west. According to this study, peak SWE is estimated to have occurred eight days earlier in the year per degree of warming. While this may not seem like much, as warming continues, this essentially means winters in Paradise Valley will become shorter and milder. Cumulatively, it found that snowpack, measured in SWE, is expected to decrease by about 25% by 2050.


In addition, this study also found in 90% of the sites monitored, that SWE depths on April 1st have declined by 21% from 1955-2016. Again, that may not seem like much, but that equates to the storage capacity of the largest reservoir in the western US, Lake Mead.


In addition to this recent study, the Greater Yellowstone Climate Assessment (GYAC) provides an in-depth look at how the Greater Yellowstone Area has been responding to climate change. Since 1950, the GYA warmed by 2.3°F, with a 2-week longer growing season. Snowfall has decreased by nearly 24 inches, or 25%, and the decline of winter happens between February and March, as opposed to April in 1950.

Impacts

Similar to the trophic cascade of the food chain, there are also trickle-down impacts in watersheds. It all starts with snowpack. Warming temperatures push the snow-line upslope, decreasing the area in which snow persists, thus declining snowpack. This change in conditions along a mountain slope can change vegetation distribution and composition. This drastically impacts evapotranspiration (ET). Climate change is expected to increase (ET), which with limited water availability perpetuates drought stress and decreases drought resiliency.


Smaller snowpacks also result in earlier spring runoff. Throughout the west, it is estimated that half of runoff is attributable to snow, while snowfall only accounts for one-third of total precipitation. Warmer temperatures at higher elevations results in more precipitation as rain, rather than snow. According to the GYAC, peak runoff is expected to be 1-2 months earlier by the end of the century. Earlier runoff suggests drier summers, potentially inducing drought stress in mountain vegetation. With drought-stressed vegetation, western forests are vulnerable to worsening wildfires, and beetle infestations and disease.

The impacts of a low-to-no-snow future goes beyond just ecological. While warmer and shorter winters mean longer growing seasons in the future, both irrigated and non-irrigated operations will have to cope with changing water supply and demand caused by smaller snowpacks, decreased runoff, and lower late-season soil moisture.



Winter recreation is also an undeniable economic and cultural asset to the GYA. Shorter winters and smaller snowpacks will affect local resorts' ability to remain safely open to recreators. Changes in elevational snowfall will also greatly impact ski resorts. The GYAC found that the number of skiable days by 2050 are expected to decline by 6 to 29 days. In addition, the length of winter in Yellowstone National Park is estimated to decrease by 16% to 27% in the latter half of the century. Both of these greatly affect the number of days tourists and locals are able to recreate, having an undeniable impact of local economies who profit from this visitation.


What can we do?

Most importantly, we need to create drought resiliency in the Valley as a preventative, mitigative measure, rather than react to future droughts in a reactionary way. In general, water management infrastructure and water rights operate under the assumption of seasonal and annual variability in snowpack in the West. However, they do so assuming stationary conditions, which, as described above, is not the case.


To be most effective in creating drought resiliency, landowners, recreators, and community members of Paradise Valley must continue education and awareness of drought conditions, as well as best practices for reducing excess water usage, land management practices, and recreating responsibly in the Valley.


In addition to being proactive in limiting climate change by decreasing our carbon footprint, being resilient to future droughts and a low-to-no-snow future is essential to mitigating the negative impacts of climate change in Paradise Valley.



References

Hostetler S, Whitlock C, Shuman B, Liefert D, Drimal C, Bischke S. 2021. Greater Yellowstone climate

assessment: past, present, and future climate change in greater Yellowstone watersheds. Bozeman

MT: Montana State University, Institute on Ecosystems. 260 p. https://doi.org/10.15788/GYCA2021.


Siirila-Woodburn, E.R., Rhoades, A.M., Hatchett, B.J. et al. A low-to-no snow future and its impacts on water

resources in the western United States. Nat Rev Earth Environ2, 800–819 (2021).

https://doi.org/10.1038/s43017-021-00219-y



Written by: Bailey Servais



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