The intense storm system that first came ashore across the West Coast on Thursday continues to cause problems in California, this time mainly in southern parts of the state. A narrow but thick plume of moisture from the tropics, also known as the "Pineapple Express," took aim at San Diego and the Los Angeles area on Friday morning.
Flash flood warnings have been issued for parts of the L.A. area and portions of the San Diego metro area. Of particular concern is the surroundings of Silverado Canyon, where rain following a wildfire burn scar is destabilizing the soil, and leading to debris flows.
The steadiest rain is likely to end in Los Angeles and San Diego by early afternoon, giving way to a threat of thunderstorms, including a low chance of tornadoes.
Meanwhile, in the Sierra Nevada and San Gabriel Mountains, heavy snow is falling, with more than 2 feet forecast in some cases.
So far, the storm has dumped up to nearly 15 inches of rain in central and northern California, with heavy rains of around 9 inches falling in the Napa and Sonoma Valleys, resulting in widespread flooding in wine country.
San Francisco recorded 3.46 inches of rain, while the 3.23 inches that fell in San Jose set a record for the wettest December day.
Yesterday's rain total of 3.23" in San Jose. It's the wettest December day ever recorded at the site. Records back to 1893. #BayAreaStorm— NWSBayArea (@NWSBayArea) December 12, 2014
Update: Latest Russian R @ Guerneville 4cast just issued by our hydrologists. Flood stage expected #NorCalStorm #cawx pic.twitter.com/5Y1Dijxj2M— NWS CNRFC (@NWSCNRFC) December 12, 2014
Rainfall rates in the L.A. and San Diego areas have been recorded as high as half an inch per hour on Friday morning.
These rains have led to mudslides and debris flows in some areas of steep terrain.
Mudslide update! “@NWSLosAngeles: Major mud/debris flows occurred at Camarillo Springs earlier this morning. pic.twitter.com/p72tUrv6p1”— Ginger Zee (@Ginger_Zee) December 12, 2014
An excavator was consumed by the #CamarilloSprings mudslides. It was brought in to clear culverts before the storm. pic.twitter.com/tjCS25S23e— Q McCray (@ABC7QMcCray) December 12, 2014
However, the mountain snow has created some gorgeous scenes.
Snow has fallen on San Emigdio (6000 ft). Camera located near Pine Mountain Club along the Ventura/Kern County border pic.twitter.com/6NLGnKBHM4— NWS Los Angeles (@NWSLosAngeles) December 12, 2014
Now that the blizzard conditions have subsided we're treated to a gorgeous view in the Sierra! #StormOfTheYear pic.twitter.com/9P0wKY9JkS— Jordan Treece (@JTreece406) December 12, 2014
While the precipitation helps California climb out of its extraordinary precipitation deficit, given that it's going through the worst drought in at least 1,200 years, the storm will not end the drought on its own. Instead, it will take several more storms of this severity to diminish the surface drought, while the groundwater deficit will take far longer to address.
Courtesy of ESRI, the following live maps can be configured to include social media reports for tracking the storm: