Issue |
E3S Web of Conf.
Volume 415, 2023
8th International Conference on Debris Flow Hazard Mitigation (DFHM8)
|
|
---|---|---|
Article Number | 04006 | |
Number of page(s) | 4 | |
Section | Role of Disturbance | |
DOI | https://doi.org/10.1051/e3sconf/202341504006 | |
Published online | 18 August 2023 |
Snowmelt-triggered debris flows in seasonal snowpacks
1 Division of Atmospheric Sciences, Desert Research Institute, Reno, Nevada, USA
2 Division of Earth and Ecosystem Sciences, Desert Research Institute, Reno, Nevada, USA
3 Center for Western Weather and Water Extremes, Scripps Institution of Oceanography, La Jolla, California, USA
4 California Geological Survey, Sacramento, California, USA
* Corresponding author: benjamin.hatchett@dri.edu
Snowmelt-triggered debris flows commonly occur in mountains. On 14 June 2019, a debris flow occurred on a steep, east-facing slope composed of unconsolidated glacial and periglacial sediments in Yosemite National Park. Originating as a shallow landslide, ~1,300m3 of ripe snow was instantaneously entrained into the debris flow carrying boulders, trees, and soil downslope. The forested area at the toe of the slope strained out debris leaving a muddy slurry to issue across Highway 120 during dewatering. We document this mass movement and assesses its initiation using local snowpack and meteorological data as well as a regional atmospheric reanalysis to examine synoptic conditions. A multiday warming trend and ripening of the snowpack occurred prior to the event as a 500 hPa ridge amplified over western North America leading to record warm 700 hPa temperatures. Anomalous temperatures and cloud cover prevented refreezing of the snowpack and accelerated its ripening with meltwater contributing to soil saturation. Similar conditions occurred during the catastrophic 1983 Slide Mountain debris flow, also hypothesized to be snowmelt initiated. With projected increases in heat waves, our findings can support natural hazard early warning systems in snow-dominated environments.
© The Authors, published by EDP Sciences, 2023
This is an Open Access article distributed under the terms of the Creative Commons Attribution License 4.0, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
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