Flash Flooding and Debris Flows in California, January 5 to 8, 2016

Mission Beach Lifeguards reported surf to 8 Ft.

The San Diego River at Fashion Valley crested above action stage 4 times, and above flood stage once between the afternoon of the 5th and the afternoon of the 7th. The river remained above action stage for almost this entire time, except for a brief period below that level during the afternoon of the 6th. Flood stage was reached between 1930-2130 PST on the 5th, cresting at 11.9 feet around 2000 PST. This resulted in mostly minor flooding of surrounding areas in Mission Valley, including low water crossings and nearby parking lots.

CHP reported mud and two large boulders several feet in diameter blocking Highway 78 at Horizon View Drive, as well as large rocks and debris on Highway 78 near Ramona View Drive.

CHP reported a mud and rock slide at La Cresta Road and Coyote Ridge Road in Granite Hills, just east of El Cajon.

Snowfall began during the evening of the 5th, continued in a few main heavy periods, and wrapping up by the afternoon of the 7th. Criteria was met sometime in the evening of the 6th. Two-day snowfall totals for San Bernardino County mountain locations include: 24 inches in Forest Falls near Highway 38 (downed trees and power lines), 18 inches at the end of Mount Baldy Road outside the village, 17 inches at the Big Bear Lake COOP (2.04 liquid equiv), 12 inches in Wrightwood/Big Bear City/Snow Summit/Arrowbear Lake, and 9 inches in Barton Flats.

Snowfall began during the evening of the 5th, continued in a few main heavy periods, and wrapping up by the afternoon of the 7th. Criteria was met sometime in the evening of the 6th. Two-day snowfall totals for San Diego County mountain locations include: 12 to 15 inches at the Mount Laguna Observatory and 7 inches at Palomar Mountain.

Snowfall began during the evening of the 5th, continued in a few main heavy periods, and wrapping up by the afternoon of the 7th. Criteria was met sometime in the evening of the 6th. Two-day snowfall totals for Riverside County mountain locations include: 14-16 inches at Pine Cove and Fern Valley near Idyllwild and 23 inches at the Long Valley Ranger Station in San Jacinto State Park.

Orange County Public Works reported three moderate debris flows in the Silverado Canyon area between 1200-1400 PST on the 6th. The first was 40-50 cubic yards long and occurred at Silverado Canyon Road and Hafra Way blocking the road. The second was at the K-rail 100-200 feet past Smeisic Ranch, was 1-2 feet deep and 10 cubic yards long and blocked Silverado Canyon Road at that location. The third was at the Smeisic Ranch ravine about 20-30 cubic yards across but did not cross the road. The road was cleared and re-opened at 0100 on the 7th. As of 1330 PST, rainfall amounts over past 6 hours were 1.22 inches, 0.94 inches over past 3 hours and 0.39 inches over past hour at Silverado Motorway Gage. Rainfall of 2.2 inches over past 6 hours, 1.65 inches over past 3 hours, and 0.71 inches over past hour were observed at Upper Silverado Canyon.

A 60 mph wind gust was recorded at the Fremont Canyon RAWS station in the Santa Ana foothills as a line of storms moved through the area.

CHP reported the Devore Road off-ramp from I-215 was closed due to flooding, as well as boulders blocking the down-bound lanes of Highway 18 south of Crestline. Broadcast media reported San Timoteo Canyon Road closed south of Redlands because of a mud and rock slide.

A funnel cloud was sighted by several people in south San Clemente near the Orange County and San Diego County border. One house was damaged, though most likely wet microburst damage, tornado not confirmed.

A spotter reported 6 of mud on Santiago Canyon Road at Lakeview in the city of Orange.

CHP reported flooding on I-5 near the Avenida Pico exit.

Sections of two stable roofs torn off by strong thunderstorm wind gusts at the San Luis Rey Equestrian Training Facility. An NWS employee went to survey and take pictures of the damage.

A 20-foot tree was knocked over by thunderstorm wind gusts estimated around 50 mph. The tree blocked Fortuna Ranch Road.

A mesonet station approximately a mile WSW of the Carlsbad-Palomar Airport recorded two gusts to 62 mph as a line of storms passed through the area between 1450-1510 PST.

Strong thunderstorm winds damaged 8 buildings and downed power lines in Vista. A tornado is possible, but still under investigation.

An NWS employee reported 15 trees snapped or uprooted near Poway Road and Sabre Springs Road, with some being as large as 18 inches in diameter. Broadcast media reported strong winds in Poway toppled a tree, which fell onto a car.

A roof collapsed at the FedEx building in Miramar.

CHP reported the 14th street off-ramp on Highway 91 in Riverside was closed due to flooding.

CHP reported a car stuck in a mudslide on De Luz Road west of Temecula.

CHP reported the northbound off-ramp from Interstate 5 to Grand Avenue was closed due to severe flooding, as well as the Genesee Avenue off-ramp from Interstate 5 was flooded with several cars stuck. TV media reported a sinkhole at the end of Avenida de la Playa in la Jolla as a result of the heavy rain. A little further south the public reported 6-12 of water flowing down Newport Avenue, over the sidewalks with minor flooding of local businesses in Ocean Beach. The public reported Ward Road in Mission Valley was flooded with several cars submerged. Nine high water rescues were performed in the greater San Diego area on January 6th.

An NWS San Diego employee reported flash flooding near Los Coches and Business 8 with between 6 inches and 2.5 feet of water flowing over the road, as well as flash flooding near El Cajon Blvd. and Main Street with 6-12 of water flowing over the road. A local spotter reported 1.5 feet of water on Johnson Ave. next to Parkway Plaza in El Cajon.

CHP reported 6 inches of water covering Dillon road at Avenida Manzana, as well as minor flooding on Highway 111 near Jefferson Street in Indio.

Mission Beach Lifeguards reported 10 to 12 ft surf with sets to 15 ft.

Huntington Beach Lifeguards reported 7 to 10 ft surf, with max sets of 15 ft on the morning of the 8th.

San Clemente Beach Lifeguards reported 6 to 8 ft surf.

Solana Beach Lifeguards reported 6 to 8 ft surf.

A mudslide in the Rancho San Diego area of El Cajon on Willow Glen sent mud flowing into several homes and closed Dehesa Elementary School for at least 2 days. Nearby, the public reported 6 inches of mud across all lanes at Dehesa Road near Stallion Oaks Road.