From a water supply management perspective, sequential years of snow drought can be a massive challenge for meeting downstream needs. Typically, water managers expect the snowpack to accumulate through April 1, which is considered the average date of maximum SWE. Reservoirs fed by snowmelt are governed by operating guidelines that are based upon this April 1 date, so that they are prepared to fill in the springtime in anticipation of the summer months.
Future Predictions and Implications
Studies show that not only will less water be stored in the snowpack on average, but snowmelt will begin earlier in the season and more slowly (due to less radiative energy available to melt the snowpack during the winter months). Additionally, the date of maximum SWE will shift to be earlier in the season. This will certainly increase the level of uncertainty for water managers, which can lead to more conservative (but not necessarily efficient) decision-making regarding water supplies. Ultimately, the increase in the incidence of flooding caused by rain-on-snow events will throw another variable in the mix for water management. Economically, sectors that are impacted by snow drought range from hydropower to agriculture to recreation. Ecologically, the effects of snow drought are much more difficult, if not impossible, to mitigate.
I wasn’t living in California during the drought of 2012-2016, but it has been hard not to notice the impacts. Enormous swaths of trees that died from water stress, disease, and insect infestations; no salmon spawning in my parents’ backyard creek for years; a new statewide groundwater management law; improvements in municipal water use monitoring and efficiency. As Lund et al. aptly state, “In California and every other water system, droughts usefully expose weaknesses and inadequate preparation in water management.” As the Western U.S. experiences a shift in snowpack dynamics, it will require a concurrent fluidity, innovativeness, and flexibility in water management.
With the complexity of water distribution systems in the west, many communities are disconnected from their water supply. They can’t see the dry patches up high on the mountains grow bigger or watch the snowlines creep higher as the sun beats down in a cloudless sky. They may not even know if any of the water coming out of their faucet comes from snowmelt. In fact, their water may come from mountains hundreds of miles, or states away.
As a skier and a scientist, I’m always watching the snowpack across the west and in my backyard. As someone who relies on snow for water supply, ecosystem services, and personal joy, it’s a blessing and a curse being so connected to your local hydrology. I watched the Tahoe area go from near-normal snowpack in mid-January to around half of that snow disappearing during California’s driest February on record. Last year, this area experienced its wettest February on record. For comparison, Alpine Meadows ski resort reported 235” snowfall in February 2019, and only 2” in February 2020.
There is no such thing as “normal” in the Sierra, but it is hard not to feel like things are shifting to a new “not-normal.” Across the Western US, only time will tell how and when climate change projections play out in terms of snowpack. In the meantime, I’ll be trying to get in as much skiing while I still can.
Danielle Perrot provided a glimpse into the impacts of climate change on natural resources on the West Coast. Check out an additional post in this series focused on the East Coast to learn how climate change impacts vary based on geographic region.
Visit Danielle Perrot’s expert profile for more information on her experience in hydrology.
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