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Watershed memory amplified the Oroville rain-on-snow flood of February 2017
Mountain snowpacks are transitioning to experience less snowfall and more rainfall as the climate warms, creating more persistent low- to no-snow conditions. This precipitation shift also invites more high-impact rain-on-snow (ROS) events, which have historically yielded many of the largest and most...
Autores principales: | , , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
Oxford University Press
2022
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9832955/ https://www.ncbi.nlm.nih.gov/pubmed/36712942 http://dx.doi.org/10.1093/pnasnexus/pgac295 |
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author | Haleakala, Kayden Brandt, W Tyler Hatchett, Benjamin J Li, Dongyue Lettenmaier, Dennis P Gebremichael, Mekonnen |
author_facet | Haleakala, Kayden Brandt, W Tyler Hatchett, Benjamin J Li, Dongyue Lettenmaier, Dennis P Gebremichael, Mekonnen |
author_sort | Haleakala, Kayden |
collection | PubMed |
description | Mountain snowpacks are transitioning to experience less snowfall and more rainfall as the climate warms, creating more persistent low- to no-snow conditions. This precipitation shift also invites more high-impact rain-on-snow (ROS) events, which have historically yielded many of the largest and most damaging floods in the western United States. One such sequence of events preceded the evacuation of 188,000 residents below the already-damaged Oroville Dam spillway in February 2017 in California’s Sierra Nevada. Prior studies have suggested that snowmelt during ROS dramatically amplified reservoir inflows. However, we present evidence that snowmelt may have played a smaller role than previously documented (augmenting terrestrial water inputs by 21%). A series of hydrologic model experiments and subdaily snow, soil, streamflow, and hydrometeorological measurements demonstrate that direct, “passive” routing of rainfall through snow, and increasingly efficient runoff driven by gradually wetter soils can alternatively explain the extreme runoff totals. Our analysis reveals a crucial link between frequent winter storms and a basin’s hydrologic response—emphasizing the role of soil moisture “memory” of within-season storms in priming impactful flood responses. Given the breadth in plausible ROS flood mechanisms, this case study underscores a need for more detailed measurements of soil moisture along with in-storm changes to snowpack structure, extent, energy balance, and precipitation phase to address ROS knowledge gaps associated with current observational limits. Sharpening our conceptual understanding of basin-scale ROS better equips water managers moving forward to appropriately classify threat levels, which are projected to increase throughout the mid-21st century. |
format | Online Article Text |
id | pubmed-9832955 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2022 |
publisher | Oxford University Press |
record_format | MEDLINE/PubMed |
spelling | pubmed-98329552023-01-26 Watershed memory amplified the Oroville rain-on-snow flood of February 2017 Haleakala, Kayden Brandt, W Tyler Hatchett, Benjamin J Li, Dongyue Lettenmaier, Dennis P Gebremichael, Mekonnen PNAS Nexus Research Report Mountain snowpacks are transitioning to experience less snowfall and more rainfall as the climate warms, creating more persistent low- to no-snow conditions. This precipitation shift also invites more high-impact rain-on-snow (ROS) events, which have historically yielded many of the largest and most damaging floods in the western United States. One such sequence of events preceded the evacuation of 188,000 residents below the already-damaged Oroville Dam spillway in February 2017 in California’s Sierra Nevada. Prior studies have suggested that snowmelt during ROS dramatically amplified reservoir inflows. However, we present evidence that snowmelt may have played a smaller role than previously documented (augmenting terrestrial water inputs by 21%). A series of hydrologic model experiments and subdaily snow, soil, streamflow, and hydrometeorological measurements demonstrate that direct, “passive” routing of rainfall through snow, and increasingly efficient runoff driven by gradually wetter soils can alternatively explain the extreme runoff totals. Our analysis reveals a crucial link between frequent winter storms and a basin’s hydrologic response—emphasizing the role of soil moisture “memory” of within-season storms in priming impactful flood responses. Given the breadth in plausible ROS flood mechanisms, this case study underscores a need for more detailed measurements of soil moisture along with in-storm changes to snowpack structure, extent, energy balance, and precipitation phase to address ROS knowledge gaps associated with current observational limits. Sharpening our conceptual understanding of basin-scale ROS better equips water managers moving forward to appropriately classify threat levels, which are projected to increase throughout the mid-21st century. Oxford University Press 2022-12-16 /pmc/articles/PMC9832955/ /pubmed/36712942 http://dx.doi.org/10.1093/pnasnexus/pgac295 Text en © The Author(s) 2022. Published by Oxford University Press on behalf of the National Academy of Sciences. https://creativecommons.org/licenses/by/4.0/This is an Open Access article distributed under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0/), which permits unrestricted reuse, distribution, and reproduction in any medium, provided the original work is properly cited. |
spellingShingle | Research Report Haleakala, Kayden Brandt, W Tyler Hatchett, Benjamin J Li, Dongyue Lettenmaier, Dennis P Gebremichael, Mekonnen Watershed memory amplified the Oroville rain-on-snow flood of February 2017 |
title | Watershed memory amplified the Oroville rain-on-snow flood of February 2017 |
title_full | Watershed memory amplified the Oroville rain-on-snow flood of February 2017 |
title_fullStr | Watershed memory amplified the Oroville rain-on-snow flood of February 2017 |
title_full_unstemmed | Watershed memory amplified the Oroville rain-on-snow flood of February 2017 |
title_short | Watershed memory amplified the Oroville rain-on-snow flood of February 2017 |
title_sort | watershed memory amplified the oroville rain-on-snow flood of february 2017 |
topic | Research Report |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9832955/ https://www.ncbi.nlm.nih.gov/pubmed/36712942 http://dx.doi.org/10.1093/pnasnexus/pgac295 |
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