National Weather Service United States Department of Commerce

Atmospheric River Bringing Heavy Rain to Southern California and Heavy Snow to the Sierra Nevadas

A strong atmospheric river will continue heavy rain over southern California through Friday. The heaviest rainfall is ongoing today in the Los Angeles Basin. Flash and urban flooding is possible. A prolonged heavy snowfall has begun over the Sierra Nevada Mountains and will continue through Friday. Travel will become increasingly difficult over the passes due to snow and strong winds. Read More >

This is a loop of 3.9 micron satellite imagery. This is a near-infrared channel that is sensitive to temperatures.

The image at 0130Z (530 pm PST) shows a black spot at Mt St Helens, indicating very warm temperatures. The subsequent images show the cooling of the volcano, as well as the drifting ash cloud to the east.

Ash plume on satellite image loop