First Advisor

Kelly Gleason

Term of Graduation

Fall 2024

Date of Publication

1-22-2025

Document Type

Thesis

Degree Name

Master of Science (M.S.) in Environmental Science and Management

Department

Environmental Science and Management

Language

English

Subjects

Forest Fires, Mid-Winter Snowmelt, Rain on Snow, Snow Hydrology

Physical Description

1 online resource (vi, 82 pages)

Abstract

As the spatiotemporal overlap between burned forests, seasonal snow, extreme precipitation, and mid-winter warming continues to increase with climate change, it is critical we quantify the impacts of forest fires and rain-on-snow (ROS) on mid-winter snowmelt and snow-water resources. In the Pacific Northwest, the release of large volumes of meltwater to downstream receiving water from already vulnerable snowpacks can have catastrophic consequences. I show that forest fires doubled mid-winter snowmelt proportions as compared to unburned reference sites, using a novel network of snow monitoring and micrometeorological stations installed across an elevational and forest type gradient in a burned watershed in the western Oregon Cascades. I also observed an increase in snowpack vulnerability during ROS events in the burned forests, particularly at mid elevations, where ROS induced snowmelt accounted for 22.5% more of annual snowmelt. As a result, total springtime snowpack storage was reduced by half compared to the unburned sites, due to more snowpack loss during midwinter rain-on-snow events than at the unburned sites. Higher net snowpack energy, driven primarily by longwave radiation at the lower and middle elevations, indicates minimal buffering capacity of these warm snowpacks in high density burned forest to increasingly common ROS events. Balancing preparations for mid-winter flooding due to increased ROS vulnerability and refining the timing of water storage to offset accelerated snow disappearance represents a pressing challenge for water managers in a changing climate.

Rights

In Copyright. URI: http://rightsstatements.org/vocab/InC/1.0/ This Item is protected by copyright and/or related rights. You are free to use this Item in any way that is permitted by the copyright and related rights legislation that applies to your use. For other uses you need to obtain permission from the rights-holder(s).

Comments

Funding support from the United States Army Corps of Engineers, Research and Development Center, contract #W912HZ2220004.

Persistent Identifier

https://archives.pdx.edu/ds/psu/42994

Included in

Hydrology Commons

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