Declines in Peak Snow Water Equivalent and Elevated Snowmelt Rates Following the 2020 Cameron Peak Wildfire in Northern Colorado

American Geophysical Union (AGU) | March 28th, 2023

The loss of tree canopy greatly increases the amount of solar energy that reaches the snow surface. Soot and debris from burned trees make the snow surface darker, result

The loss of tree canopy greatly increases the amount of solar energy that reaches the snow surface. Soot and debris from burned trees make the snow surface darker, resulting in more of this energy being absorbed. Late-season snow storms were able to temporarily counteract some of these effects by burying the darker snow surface. As more and more of the western United States is fire-impacted, it is essential to better understand and account for these impacts on this critical water reservoir for this region.

Delta Adapts: Creating a Climate Resilient Future

Delta Stewardship Council (Delta Council) | June 25th, 2021

The time to act is now. Climate change is already altering the physical environment of the Sacramento–San Joaquin Delta and Suisun Marsh (Delta), and we will continue t

The time to act is now. Climate change is already altering the physical environment of the Sacramento–San Joaquin Delta and Suisun Marsh (Delta), and we will continue to experience its effects through hotter temperatures, more severe wildfires, and prolonged droughts. Over the long term, climate change in the Delta is expected to harm human health and safety, disrupt the economy, diminish water supply availability and usability, shift ecosystem function, compromise sensitive habitats, and increase the challenges of providing basic services. Many of these impacts will disproportionately affect vulnerable communities. Although the exact extent and timing of these impacts is uncertain, this climate change vulnerability assessment phase of Delta Adapts will help the Delta Stewardship Council (Council) understand specific regional climate risks and vulnerabilities. Regional, collaborative adaptation strategies rooted in science are more critical than ever. The next phase of Delta Adapts, preparing an adaptation strategy, will identify ways to address the risks and vulnerabilities.

Effects of wildfire on benthic macroinvertebrate assemblages in Southern California streams and implications for bioassessment monitoring programs

California State Water Resources Control Board (SWRCB) | June 13th, 2012

Wildfires are common in arid regions of southern California, sometimes burning as much as half a million acres in a season. These fires often cause dramatic impacts to th

Wildfires are common in arid regions of southern California, sometimes burning as much as half a million acres in a season. These fires often cause dramatic impacts to the vegetation and soils of regional watersheds and, consequently, to the streams that drain them. Water quality programs that monitor and regulate these systems have to account for the influence of these factors upon water quality measurements when making monitoring and regulatory decisions. This is true for traditional water quality measures (nutrients, metals, contaminants, etc.), but is especially important for integrative ecological condition indicators like bioassessment, the use of resident biological communities to infer water quality condition.

Escalating Hydrological Extremes and Whiplashes in the Western U.S.: Challenges for Water Management and Frontline Communities

American Geophysical Union (AGU) | May 14th, 2025

Fire and Water: Assessing Drinking Water Contamination After a Major Wildfire

American Chemical Society (ACS) | August 2nd, 2021

We investigated patterns of volatile organic compound (VOC) contamination in drinking water systems affected by the California 2018 Camp Fire. We performed spatial analys

We investigated patterns of volatile organic compound (VOC) contamination in drinking water systems affected by the California 2018 Camp Fire. We performed spatial analysis of over 5000 water samples collected over a 17 month period by a local water utility, sampled tap water for VOCs in approximately 10% (N = 136) of standing homes, and conducted additional nontargeted chemical analysis of 10 samples. Benzene contamination was present in 29% of service connections to destroyed structures and 2% of service connections to standing homes. A spatial pattern was apparent. Tap water in standing homes 11 months after the fire contained low concentrations of benzene in 1% of samples, but methylene chloride was present in 19% of samples, including several above regulatory limits. Elevated methylene chloride was associated with greater distance from the water meter to the tap, longer stagnation time, and the presence of a destroyed structure on the service connection; it was inversely associated with certain trihalomethanes. Nontargeted analysis identified multiple combustion byproducts in the water at 2/10 homes. Our findings support the hypothesis that pyrolysis and smoke intrusion from depressurization contributed to the benzene contamination. Further research is needed to test the hypothesis that methylene chloride may be generated from the dehalogenation of disinfection byproducts stagnating in galvanized iron pipes.

Fire influence on land–water interactions in aridland catchments

Oxford University Press (OUP) | January 9th, 2025

Wildfires have increased in size, frequency, and intensity in arid regions of the western United States because of human activity, changing land use, and rising temperatu

Wildfires have increased in size, frequency, and intensity in arid regions of the western United States because of human activity, changing land use, and rising temperature. Fire can degrade water quality, reshape aquatic habitat, and increase the risk of high discharge and erosion. Drawing from patterns in montane dry forest, chaparral, and desert ecosystems, we developed a conceptual framework describing how interactions and feedbacks among material accumulation, combustion of fuels, and hydrologic transport influence the effects of fire on streams. Accumulation and flammability of fuels shift in opposition along gradients of aridity, influencing the materials available for transport. Hydrologic transport of combustion products and materials accumulated after fire can propagate the effects of fire to unburned stream–riparian corridors, and episodic precipitation characteristic of arid lands can cause lags, spatial heterogeneity, and feedbacks in response. Resolving uncertainty in fire effects on arid catchments will require monitoring across hydroclimatic gradients and episodic precipitation.

Growing human-induced climate change fingerprint in regional weekly fire extremes

Nature Portfolio (Springer Nature) | April 23rd, 2025

Impact of current and warmer climate conditions on snow cover loss in burned forests

American Association for the Advancement of Science (AAAS) | September 17th, 2025

Wildfires are increasingly burning in snow-dominated watersheds and can alter snowmelt dynamics. However, the spatial variability of snow cover loss in burned forests has

Wildfires are increasingly burning in snow-dominated watersheds and can alter snowmelt dynamics. However, the spatial variability of snow cover loss in burned forests has been under characterized. Here, we use remotely sensed snow data to show that, under average winter conditions, snow melts earlier in the first year postfire in 99% of the snow zone. Postfire snow cover loss is more extreme in relatively low-elevation, warm environments compared to that in high-elevation, cold regions. Under +2°C of warming, 73% of the snow zone would experience more extreme earlier postfire snowmelt compared to historically average conditions. Regions with the largest shift earlier in postfire snowmelt timing under average climate conditions also have the largest shift earlier in postfire snowmelt under +2°C warming. The spatial variability in postfire snowmelt timing and exacerbated impact in projected warmer winters affect ecosystem water availability, snow albedo feedbacks, and snowmelt runoff forecasting essential to water resource management.

Increasing Hydroclimatic Whiplash Can Amplify Wildfire Risk in a Warming Climate

Global Change Biology (Wiley) | February 7th, 2025

The catastrophic January 2025 fires were propelled by an especially extreme combination of these two recognized risk factors: (1) downslope wind gusts over 80 mph (35 m/s

The catastrophic January 2025 fires were propelled by an especially extreme combination of these two recognized risk factors: (1) downslope wind gusts over 80 mph (35 m/s) and exceptionally dry vegetation following a historically dry start to the rainy season and unusually warm antecedent temperatures driving a prolonged episode of elevated atmospheric evaporative demand. But there was also a third contributor: two consecutive anomalously wet winters (in 2022–2023 and 2023–2024), which led to abundant growth of herbaceous vegetation across CSC. This remarkable wet-to-dry sequence, therefore, set the stage for the CSC wildfire disasters to unfold by first facilitating prodigious fuel accumulation during the previous growing seasons, then subsequently drying vegetation to produce exceptional flammability unusually far into winter (when Santa Ana winds are common). Globally, climate change has increased wildfire potential primarily through greater aridity (Jain et al. 2022). In CSC, hotter summer and autumn seasons drive this aridity by increasing evaporative demand (i.e., atmospheric “thirst”), subsequently drying out vegetation. This, in conjunction with an increasingly delayed onset of the rainy season (Goss et al. 2020), may also be increasing temporal overlap between critically dry vegetation and Santa Ana winds (Swain 2021). As the events of January 2025 vividly illustrate, however, transitions from anomalously wet to anomalously dry conditions may further amplify these risks by exacerbating fuel accumulation and desiccation cycles. Indeed, in fire regimes (including CSC) where fire occurrence varies strongly with inter-annual variations in biomass (Swetnam et al. 2016), increased hydroclimate volatility is causally linked to increased wildfire activity.

Metals in Wildfire Suppressants

American Chemical Society (ACS) | October 30th, 2024