Piecuch, C. G., S. Coats, S. Dangendorf, F. W. Landerer, J. T. Reager, P. R. Thompson, and T. Wahl. 2022. High-Tide Floods and Storm Surges During Atmospheric Rivers on the US West Coast.  Geophysical Research Letters, 49(2), doi/10.1029/2021GL096820

 

Atmospheric rivers (ARs) drive hydrological hazards over land related to extreme precipitation. As they make landfall, ARs typically bring heavy rains, strong winds, and low pressures to the coast.  While these factors can cause storm surge and coastal flooding, little attention has been paid to possible coastal impacts of ARs. We establish relationships between ARs and high-tide floods (HTFs) on the US West Coast and identify the factors causing storm surge during ARs.  HTFs occur at nearly the same time that ARs make landfall more often than expected from chance,  suggesting that ARs contribute importantly to HTFs. Even so, few ARs lead to HTFs—favorable tides or mean sea-level anomalies are usually needed on top of the storm surge from an AR to cause an HTF. Storm surge during an AR can be explained by the heavy rain, strong wind, and low pressure typically associated with the event; wind and pressure are the primary factors causing the surge, but rainfall can also have a secondary influence. Our results highlight that HTFs arise from the subtle interweaving of storm surge, tide, and mean sea-level effects, thus providing important information to managers and modelers, and motivating future studies on relationships between ARs and coastal hazards globally.

This research was funded by the National Aeronautics and Space Administration (award 80NSSC20K1241) and published in the journal Geophysical Research Letters.