PUBLICATION HIGHLIGHT

New study examines atmospheric river flood event under future conditions

Flooding at Montana’s Glacier National Park produced by an inland-penetrating atmospheric river in November 2006 (National Park Service). This event served as the “present-day” flood case for this study.
Flooding at Montana’s Glacier National Park produced by an inland-penetrating atmospheric river in November 2006 (National Park Service). This event served as the “present-day” flood case for this study.

In November 2006, Montana’s Glacier National Park experienced an extreme precipitation event, which caused major flooding throughout the area. In a recent study led by ESRL’s Physical Sciences Division, researchers examine the potential impacts of projected temperature changes on a similar event unfolding in the future. The 2006 flood event was driven by an atmospheric river, which had penetrated inland from the West Coast. Previous research has shown that climate change is projected to potentially alter a variety of atmospheric river characteristics and impacts. These research findings – to be published in the Journal of Climate – suggest that should a similar weather event occur in warmer future conditions, precipitation would increase overall and in significant amounts in some specific inland flood-prone mountainous regions.

The high-resolution models used by the researchers indicate that a similar type of weather event occurring in warmer conditions would increase total precipitation. Precipitation associated with a similar type of landfalling atmospheric river might also penetrate further inland by way of stronger and deeper moisture transport, which could more easily spill over the Pacific Northwest’s Coastal and Cascade mountain ranges.

Also, precipitation that fell as snow in the present-day simulation becomes rain in the future simulations for many mid- and high-elevation locations, suggesting potential for enhanced flood risk for these regions in future similar events.

Studies such as this can help planners and decision-makers with scenario-based planning, offering a collection of potential future outcomes based on a particular historical event, hazard type, or phenomenon of interest.

Authors of An examination of an inland-penetrating atmospheric river flood event under potential future thermodynamic condition are: Kelly Mahoney, Dustin Swales, Mike Alexander and Mimi Hughes of the ESRL Physical Sciences Division; Mike Mueller of the ESRL Global Systems Division, and Kelly Malloy of the University of Miami.