Impacts of Wildfire on Snowpack in the Western U.S. Based on SNOTEL Observations
Abstract
Snowpack is an essential source of water supply in the western United States, and substantial changes in snowpack could have major economic impacts. In recent years, wildfires have become larger and more frequent in the West. Wildfires have the potential to impact snowpack not only by reducing or removing the vegetation cover but also by changing the land surface albedo. Several studies have examined the effects of wildfires on snowpack within various regions, but the results of those studies vary. The net effects of wildfire on snowpack phenology and the factors that determine those effects remain unclear. The objective of this study is to examine the effects of wildfire occurrence on snowpack phenology using the NRCS Snow Telemetry (SNOTEL) network. Throughout the western U.S. and Alaska, 45 SNOTEL sites were identified that have been impacted by wildfire. For each of those burned sites, at least two similar unburned SNOTEL sites were also identified. The effects of wildfire were examined by comparing the pre-fire and post-fire periods at the burned sites and by comparing the post-fire periods at the burned and unburned sites. The results were also analyzed by ecoregion, burn severity, change in leaf area index (LAI), antecedent forest composition, years since fire, and elevation. For most locations in the dataset, wildfires produced earlier maximum snow water equivalent (SWE) and melt-out dates. The effect of wildfire on maximum SWE is more variable in the dataset, but wildfires usually result in a reduction in maximum SWE. The results are relatively insensitive to burn severity estimates, but greater changes in LAI produce larger changes in the SWE. Effects of wildfire are observed to persist for at least 10 years after fire occurrence.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2021
- Bibcode:
- 2021AGUFM.H52H..06G