The western United States is facing an ongoing snow drought that has persisted into early 2026. This is surprising given the record precipitation from recent atmospheric river storms. However, these storms, rather than alleviating the drought, have contributed to it. Let’s explore what a snow drought is, and how recent weather events have affected snowpack in the region.
Understanding Snow Drought
A snow drought occurs when the snowpack’s water content is significantly lower than historical averages. Hydrologists often measure this using the snow water equivalent, which reflects the amount of water contained in the snow.
Unlike other droughts, a snow drought is characterized by a specific lack of snow even during periods of normal or above-normal precipitation. This situation can arise when warmer temperatures cause precipitation to fall as rain instead of snow, leading to what is known as a “warm snow drought.” This phenomenon has been increasingly observed across the western U.S., especially this winter.
Impact of Atmospheric Rivers
In December 2025, the Pacific Northwest experienced heavy rainfall due to a significant atmospheric river event. Between December 1 and December 15, the Cascade Mountains received up to 24 inches of rain. This resulted in severe flooding, landslides, and infrastructural damage, affecting roads and communities throughout Washington state.
- Five stream gauges in the area recorded historic flood levels.
- Sixteen other gauges reached “major flood” status.
- Vehicles were stranded as floodwaters overwhelmed levees.
Despite this intense rainfall, the overall water supply situation worsened. The warm temperatures associated with the rain melted existing snow in crucial mountain watersheds, decreasing the snowpack’s water storage by about 50% in the Yakima River Basin.
The Future Prospects for Snowpack
Fortunately, the winter season is still young, with significant snow accumulation expected until March. Recent snowfalls have begun to replenish the water lost during the December storm in the Yakima River Basin; however, levels remain below historical averages as of early January 2026.
To mitigate the impacts of snow drought, scientists and water resource managers are intensifying efforts to improve predictive models. Understanding how individual storms generate rain versus snow will enhance forecasting accuracy. This research is critical as rising temperatures make snow droughts a more frequent concern, impacting agriculture, water resources, and winter recreation across the region.
