A secondary and intensified atmospheric river is anticipated to bring severe flooding to Southern California on Sunday, following a previous storm that resulted in record rainfall in certain areas. This second atmospheric river is poised to impact central and southern California starting late Saturday night, persisting for several days.
The primary impact of this storm is expected to be felt in Southern California, particularly in the greater Los Angeles area, with the peak of flooding anticipated on Sunday. The National Weather Service in Los Angeles cautioned that there is an increasing likelihood of an extended period of heavy rain from late Saturday night through most of Sunday and Monday, potentially generating unprecedented rainfall across a broad area.
Projections suggest that more than a month’s worth of rain could occur across Southern California, with widespread rainfall totals ranging from 3 to 6 inches anticipated from late Saturday to Wednesday. This adds to the substantial rainfall experienced on Thursday when the initial atmospheric river led to record rainfall and triggered water rescues in various regions.
The forthcoming atmospheric river, characterized by a long, narrow moisture band carrying saturated air over great distances and releasing it intensely, is expected to be even more potent. It is likely to stall over land, affecting areas already saturated by Thursday’s powerful storm. The forecast indicates that periods of moderate to heavy rainfall may be nearly continuous for up to 48 hours, with Sunday and Monday posing the greatest risk of dangerous rainfall.
The potential deluge raises concerns of urban flooding, mudslides, rockslides, flash floods, and river flooding. Compounding the risk is the fact that soils are already saturated from Thursday’s storm, heightening the potential for debris flows in Southern California.