Extreme winds and precipitation during landfall of atmospheric rivers

Abstract

Atmospheric rivers—long, narrow filaments of large integrated water vapour transport—are associated with weather and water extremes, such as precipitation extremes and flooding in western North America and northern Europe. Here we apply a global detection algorithm for atmospheric rivers to reanalysis data during 1997–2014 to investigate the impact of atmospheric rivers on wind extremes as well as precipitation extremes. We find that atmospheric rivers are associated with up to half of the extreme events in the top 2% of the precipitation and wind distribution, across most mid-latitude regions globally. Landfalling atmospheric rivers are associated with about 40–75% of extreme wind and precipitation events over 40% of the world’s coastlines. Atmospheric rivers are associated with a doubling or more of the typical wind speed compared to all storm conditions, and a 50–100% increase in the wind and precipitation values for extreme events. We also find that the majority of extreme wind events catalogued between 1997 and 2013 over Europe with billion US dollar losses were associated with atmospheric rivers. We conclude that landfalling atmospheric rivers can represent a significant hazard around the globe, because of their association with not only extreme precipitation, but also extreme winds. Atmospheric rivers have been associated with extreme rainfall events. A global detection algorithm, applied to reanalysis data, suggests that they contribute substantially to extremes in wind as well as precipitation along coasts globally.