A West Coast trough of low pressure impacted Southern California March 9th through 13th. This storm brought periods of windy conditions across the mountains and deserts, along with widespread rain and snowfall, and areas of flooding and debris flows being observed as well.

High Wind in SAN DIEGO COUNTY MOUNTAINS, CALIFORNIA
From 09-MAR-21 00:00:00 to 11-MAR-21 00:00:00 (PST-8)
Magnitude: 85.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

Gusty winds occurred across the region, mostly 45-60 MPH with localized pockets of higher gusts.

High Wind in SAN GORGONIO PASS NEAR BANNING, CALIFORNIA
From 09-MAR-21 00:00:00 to 11-MAR-21 00:00:00 (PST-8)
Magnitude: 52.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: RAWS

Gusty winds occurred across the region, mostly 45-60 MPH.

High Wind in APPLE AND LUCERNE VALLEYS, CALIFORNIA
From 09-MAR-21 00:00:00 to 11-MAR-21 00:00:00 (PST-8)
Magnitude: 50.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

Gusty winds occurred across the region, mostly 45-60 MPH.

Heavy Snow in SAN BERNARDINO COUNTY MOUNTAINS, CALIFORNIA
From 09-MAR-21 00:00:00 to 13-MAR-21 09:00:00 (PST-8)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Multiple members of the public and ski resorts report storm total snow one to two feet across the region.

Heavy Snow in RIVERSIDE COUNTY MOUNTAINS, CALIFORNIA
From 09-MAR-21 00:00:00 to 13-MAR-21 09:00:00 (PST-8)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Park/Forest Service

Reports of 6-12 inches of storm total snow occurred across the region.

Heavy Snow in SAN BERNARDINO AND RIVERSIDE COUNTY VALLEYS - THE INLAND EMPIRE, CALIFORNIA
From 09-MAR-21 00:00:00 to 13-MAR-21 09:00:00 (PST-8)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Official NWS Observations

Portions of the eastern Inland Empire received a couple inches of snow, such as Cherry Valley with two inches at an elevation of 5,000 feet.

Heavy Rain in SAN DIEGO, CALIFORNIA
From 09-MAR-21 00:00:00 to 13-MAR-21 09:00:00 (PST-8)
Location: PINE HILLS
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Fire Department/Rescue

Areas of the San Diego county mountains received heavy rainfall out of this storm system, with some areas over 2 inches in total. Pine Hills reported 2.82 inches of rain.

Flash Flood in ORANGE, CALIFORNIA
From 10-MAR-21 04:00:00 to 10-MAR-21 08:00:00 (PST-8)
Location: SILVERADO
Flood cause: Heavy Rain / Burn Area
Property damage: 75.00K
Crop damage: 0.00K
Reported by: Fire Department/Rescue

Confirmed 8 vehicles were damaged by a mud and debris flow on the Bond Fire. 6 homes had mud and water damaged. Swift water rescues were performed around 6 to 7 am at the peak of the mud and debris flows. Mud covered at least 3 locations on Silverado Canyon road and at Silverado Cafe. Rainfall rates as high as 0.20 inches in 15 minutes between 6 and 7 am.

Hail in RIVERSIDE, CALIFORNIA
From 11-MAR-21 14:00:00 to 11-MAR-21 18:00:00 (PST-8)
Location: MURRIETA
Magnitude: 0.50 
Property damage: 10.00K
Crop damage: 0.00K
Reported by: Social Media

Thunderstorms late afternoon on March 11 produced 1/4 to 1/2 inch hail.

Heavy Snow in SAN DIEGO COUNTY MOUNTAINS, CALIFORNIA
From 09-MAR-21 00:00:00 to 13-MAR-21 09:00:00 (PST-8)
Property damage: 10.00K
Crop damage: 0.00K
Reported by: Park/Forest Service

Reports of 6-18 inches of storm total snow occurred across the region. 6 inches of snow in 3 hours on Palomar Mountain due to thundersnow. Both locations at 5000 to 5700 feet reported total snowfall of 18 to 24 inches.

Heavy Snow in SAN DIEGO COUNTY MOUNTAINS, CALIFORNIA
From 10-MAR-21 05:00:00 to 12-MAR-21 23:00:00 (PST-8)
Property damage: 10.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Palomar Mountain reported a total of 23 inches. 6 inches occurred in 3 hours during a thunderstorm. Julian at 5000 feet report 18 inches of snow while Palomar mountain was reporting the same amount. Water equivalent was 2.5 to 3 inches.

Debris Flow in ORANGE, CALIFORNIA
From 10-MAR-21 04:00:00 to 10-MAR-21 12:00:00 (PST-8)
Location: SILVERADO
Flood cause: Heavy Rain / Burn Area
Property damage: 50.00K
Crop damage: 0.00K
Reported by: County Official

Heavy rain of near 0.20 inches in 15 minutes occurred between 6 and 7 am over Bond fire scar near the Silverado Canyon and this prompted evacuation orders of residents. The debris flow brought areas of mud and debris over roads and into homes. This caused damage to 6 homes and 8 vehicles in the town of Silverado. This also closed Silverado Canyon Road between Olive Drive and Ladd Canyon Drive.