NASA combined data from multiple satellites to estimate the rainfall from an "atmospheric river" event over the U.S. West Coast in near real-time at half-hourly intervals from January 25 - 29, 2021. Atmospheric rivers are long, narrow corridors of water vapor that can lead to heavy precipitation when they encounter land. This animation shows estimated rainfall rates in blue and yellow shading and total rainfall accumulations in green shading, from NASA's IMERG algorithm, overlaid on shades of white and gray from NOAA infrared satellite data which shows cloudiness. On January 25, 2021, a low