Atmospheric Rivers and Snow Accumulation in the Sierra Nevada Connected by Surface Air Temperature

Narrow bands of strong atmospheric moisture transport, referred to as atmospheric rivers (ARs), contribute importantly to the seasonal snow accumulation in the Sierra Nevada. About 20-40% of the snow accumulation during November-March occurred during AR events based on snow water equivalent (SWE) estimates from five water years (2004-2008). The impact of ARs on snow varies significantly from event to event. Snow sensor observations show that SWE changes associated with ARs are closely related to the mountain surface air temperature (SAT), such that colder temperatures are associated with more snow accumulation. This relationship is well captured by AIRS satellite temperature retrievals, while less well represented in the ERA-Interim reanalysis.