A low pressure system moved through Southern California March 20th and 21st and brought heavy rain, thunderstorms, and mountain snow to the area. The heaviest rainfall and snowfall occurred on the 20th, with just light showers on the 21st. Rainfall totals of 0.25 to 0.50 inch fell in the coastal areas (particularly San Diego County coastline), and up to an inch of rain fell in the valley and mountain areas. Snowfall amounts ranged from 1-4 inches above 5500 feet. Small hail and lightning occurred in thunderstorms on the 20th. Urban street flooding occurred in Orange County and at the Holy Fire Burn Scar. Rainfall rates of 0.70/hr occurred at the burn scar.

Hail in ORANGE, CALIFORNIA
From 20-MAR-19 17:00:00 to 20-MAR-19 19:00:00 (PST-8)
Location: ROSSMOOR
Magnitude: 0.25 
Property damage: 5.00K
Crop damage: 0.00K
Reported by: Department of Highways

CalTrans reported accidents on Highway 241 northbound due to hail on the road.

Hail in ORANGE, CALIFORNIA
From 20-MAR-19 15:00:00 to 20-MAR-19 16:00:00 (PST-8)
Location: YORBA LINDA
Magnitude: 0.70 
Property damage: 0.50K
Crop damage: 0.00K
Reported by: Trained Spotter

Spotter reported dime-sized hail in Yorba Linda around 1500 PST on March 20th.

Debris Flow in RIVERSIDE, CALIFORNIA
From 20-MAR-19 17:00:00 to 20-MAR-19 20:00:00 (PST-8)
Location: LAKELAND VLG
Flood cause: Heavy Rain / Burn Area
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Department of Highways

CalTrans reported roadway flooding and debris in the road on Grand Ave and Blackwell Blvd.

Winter Weather in RIVERSIDE COUNTY MOUNTAINS, CALIFORNIA
From 20-MAR-19 12:00:00 to 21-MAR-19 18:00:00 (PST-8)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Spotters reported 1-2 inches storm total snow in Idyllwild between March 20th and 21st.

Winter Weather in SAN BERNARDINO COUNTY MOUNTAINS, CALIFORNIA
From 20-MAR-19 12:00:00 to 21-MAR-19 12:00:00 (PST-8)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: CoCoRaHS

A CoCoRaHS observer reported 1.5 inches of snow at Lake Arrowhead, and another CoCoRaHS observer reported 1.2 inches of snow near Big Bear Lake.

High Surf in ORANGE COUNTY COASTAL, CALIFORNIA
From 20-MAR-19 08:00:00 to 21-MAR-19 21:00:00 (PST-8)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Lifeguard

In Orange County, lifeguards reported widespread 6 ft surf on the coast.

High Surf in SAN DIEGO COUNTY COASTAL AREAS, CALIFORNIA
From 20-MAR-19 08:00:00 to 21-MAR-19 22:00:00 (PST-8)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Lifeguard

In San Diego County, lifeguards reported widespread 6 ft surf along the coast.

Winter Weather in SAN BERNARDINO COUNTY MOUNTAINS, CALIFORNIA
From 20-MAR-19 16:00:00 to 21-MAR-19 21:00:00 (PST-8)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Spotter reported 4 inches of snow at Snow Valley (7800 ft elevation).

Heavy Rain in RIVERSIDE, CALIFORNIA
From 20-MAR-19 21:00:00 to 20-MAR-19 22:00:00 (PST-8)
Location: ARCILLA
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Rainfall rates of 0.71/hr were reported at Temescal Canyon, which is the highest hourly rainfall rate of the winter season for that canyon. In 30 minutes, 0.59 fell over Temescal Canyon. Lanes were flooded and debris was on the roadway on Temescal Canyon Road near the intersection on I-15.