February 21, 2023 – Storms delivering above-average snowfalls this year have fueled western water users’ hopes for a better season, particularly given the restrictions, shortages and worries caused by drought the past couple of summers.
But a report published last week on Drought.gov, authored by researchers Ben Hatchett and Arielle Koshkin, dampens those hopes.
The authors identify five key findings in Severe Summer Wildfires Are Impacting Western U.S. Mountain Snowpack During Winter and Spring:
- Fires are burning higher in elevation, increasing the geographical overlap between burned areas and seasonal snow zones (areas with persistent snowpack throughout the winter season).
- We found a 10-fold increase in fire in California’s seasonal snow zones in 2020–2021 versus 2001–2019.
- Wildfires accelerate snowmelt resulting in earlier snow disappearance come spring.
- Wildfire decreases the water stored in snow and alters the timing of snowmelt run-off. This creates a significant challenge for water managers to forecast runoff timing and volume.
- Dry spells, which are long periods of no precipitation, increase the effects of wildfire on snow’s ability to store water.
“Midwinter drought, snow loss, and increasingly large, frequent, and severe wildfires are all expectations of a warming world,” the authors conclude. “Addressing the challenges brought by these changes requires innovative water and forest management plans to be formulated and quickly implemented. Our findings motivate additional research into assessing and planning for post-fire hydrologic changes in snow-dominated landscapes as both wildfire and dry spells will increase in frequency with climate warming.”