Climate change drastically lowers snow's water storage capacity
Snow isn’t just for winter fun – it’s a massive natural reservoir that supplies our water long after the slopes clear. But, a new study from Oregon State University reveals a concerning trend: snow water storage in mountain snowpacks has significantly declined in recent decades across the lower 48 states.
Snow water storage refers to the amount of water contained within snowpacks, which are accumulations of snow that build up in colder climates during the winter months. The current trend could have wide-ranging consequences for our overall approach to managing water resources.
Snowpacks melting
During the cold months, snowpacks accumulate snow, which compactly stores water as ice. As temperatures rise in spring and summer, these snowpacks gradually release water. This meltwater flows into rivers and reservoirs, replenishing supplies that are critical for drinking, irrigation, and supporting aquatic ecosystems.
This process is crucial for regions relying on seasonal snowmelt as their main water source. In the western United States, it greatly affects water availability for millions of people, as well as for orchards and vineyards.
However, accurately measuring the water content of snowpacks presents a considerable challenge. Traditional methods often provide only snapshots in time or have limited spatial coverage, making it difficult to assess the overall amount of water stored and released throughout the season.
Snow water storage
To address current challenges, Professor David Hill and doctoral student Christina Aragon have developed a new metric, termed “snow water storage,” which offers an accurate assessment of the water stored in snowpacks.
“Unlike other widely used metrics that capture snow variables at a single point in time, like maximum snow water equivalent, or describe snow characteristics in terms of time, such as length of snow season, snow water storage is applicable at numerous time and space scales,” explained Hill.
“It’s really just a cumulative sum, not a maximum value; it’s like adding up the number of miles you drive in a given year, rather than just thinking about the 500 you did on one day for your road trip.”
Findings from snow water storage
The snow water storage highlights a troubling 22% decrease in the annual water stored within mountain snowpacks across the lower 48 states of the U.S. This insight into the depletion of natural water reserves in mountain areas is alarmingly significant.
Mountains play a pivotal role in water storage. Their geographical and climatic conditions allow snow to accumulate during winter months, acting as a natural reservoir that slowly releases water as it melts.
The researchers revealed that 72% of snow water storage is concentrated in mountains—areas that account for just 16% of the land in the lower 48 states. This highlights their outsized importance in the nation’s water supply system.
Role of climate change
Climate change is wreaking havoc on snowpack water storage. It is disrupting the delicate balance between the quantity and timing of water released from these natural reservoirs.
As global temperatures climb, many regions are experiencing earlier snowmelt, reduced snowfall, and skyrocketing evaporation rates. This translates to less water being stored in snow, throwing the traditional patterns of water availability.
These disruptions pose significant challenges for water management. New strategies are urgently needed to ensure a sustainable supply in the face of a more variable climate.
There’s a silver lining
Despite the challenges, there’s reason for optimism. “As we move forward, and as we have moved from the past to the present, the relatively good news is that annual precipitation amounts tend to not change that dramatically,” Hill said.
“However, changing temperatures greatly influence snow storage and therefore the timing of water availability.” This suggests that, with the right tools and strategies, we can adapt and secure a sustainable water future.
The work by Oregon State University researchers offers a powerful new tool and a renewed sense of hope. By understanding the vital role snowpacks play in our ecosystem, we can develop adaptive strategies to meet these challenges head-on.
The study is published in the journal Hydrology and Earth System Sciences.
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