High-Tide Floods and Storm Surges During Atmospheric Rivers on the US West Coast

Amospheric rivers (ARs) effect inland hydrological impacts related to extreme precipitation. However, little is known about the possible coastal hazards associated with these storms. Here we elucidate high-tide floods (HTFs) and storm surges during ARs through a statistical analysis of data from the US West Coast during 1980-2016. HTFs and landfalling ARs co-occur more often than expected from random chance. Between 10%-63% of HTFs coincide with landfalling ARs, depending on location. However, only 2%-15% of ARs coincide with HTFs, suggesting that ARs typically must co-occur with anomalously high tides or mean sea levels to cause HTFs. Storm surges during ARs are interpretable in terms of local wind, pressure, and precipitation forcing. Meridional wind and barometric pressure are the primary drivers of the storm surge. This study highlights the relevance of ARs to coastal impacts, clarifies the drivers of storm surge during ARs, and identifies future research directions