Genesis locations of the costliest atmospheric rivers impacting the Western United States (insurance claim data)

Atmospheric rivers (ARs) are responsible for the vast majority
(approximately 88%) of flood damage in the Western U.S, an annual average
of USD$1.1 billion. Here, using historical flood insurance data, we
investigate the genesis characteristics of damaging ARs in the Western
U.S. ARs exceeding USD$20 million in damage (90th percentile), are shown
to travel further across the Pacific Ocean, with median genesis locations
8° to 27° further westward compared to typical ARs. Identifying regions of
preferential genesis of damaging ARs elicit important implications for AR
observation campaigns, highlighting distant regions not currently
considered for AR reconnaissance. The genesis of damaging ARs is
associated with elevated upper-level zonal wind speeds along with deeper
cyclonic anomalies, most pronounced for Washington and Oregon ARs. Linking
AR dynamics and lifecycle characteristics to economic damage provides an
opportunity for impact-based forecasting of ARs prior to landfall,
supporting efforts to mitigate extreme flood damages.