A weakening atmospheric river drifted south into the region, bringing areas of heavy rain and gusty winds. This led to debris flows and areas of flooding, which impacted various roads and homes.

Heavy Rain in RIVERSIDE, CALIFORNIA
From 25-OCT-21 09:00:00 to 25-OCT-21 22:00:00 (PST-8)
Location: IDYLLWILD
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

Moderate to heavy rain occurred across the region with parts of the Idyllwild area receiving amounts near 0.90 inches of rain in total.

Heavy Rain in SAN DIEGO, CALIFORNIA
From 25-OCT-21 12:00:00 to 25-OCT-21 22:00:00 (PST-8)
Location: PINE HILLS
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Official NWS Observations

Moderate to heavy rain fell across the region with areas of 0.50 to 0.80 inches total.

Heavy Rain in SAN BERNARDINO, CALIFORNIA
From 25-OCT-21 11:00:00 to 25-OCT-21 22:00:00 (PST-8)
Location: UPLAND CABLE ARPT
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

The coastal slopes received between 0.50 and 0.90 inches of total rainfall.

High Wind in RIVERSIDE COUNTY MOUNTAINS, CALIFORNIA
From 25-OCT-21 12:00:00 to 25-OCT-21 18:00:00 (PST-8)
Magnitude: 75.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

Gusty winds occurred across the region with mesonet Toro Peak measuring peak wind gust of 86 MPH.

High Wind in SAN DIEGO COUNTY MOUNTAINS, CALIFORNIA
From 25-OCT-21 12:00:00 to 25-OCT-21 18:00:00 (PST-8)
Magnitude: 57.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

Gusty winds occurred across the region with mesonet Volcan Mountain measuring a peak wind gust of 61 MPH.

Debris Flow in SAN BERNARDINO, CALIFORNIA
From 25-OCT-21 13:00:00 to 25-OCT-21 18:00:00 (PST-8)
Location: TWIN PEAKS
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Department of Highways

A large boulder was in a lane of Highway 18 at Gregory Lane reported on Quickmap via CHP Caltrans. Heavy rain band moved through this area with rain rates of 0.70 inch per hour.

Debris Flow in SAN BERNARDINO, CALIFORNIA
From 25-OCT-21 14:00:00 to 25-OCT-21 20:00:00 (PST-8)
Location: LAKE ARROWHEAD
Flood cause: Heavy Rain
Property damage: 5.00K
Crop damage: 0.00K
Reported by: Department of Highways

Hospital Road and State Route 173 roadway damage reported from heavy rain. 1.18 inches rainfall in 3 hours reported nearby.

Debris Flow in SAN BERNARDINO, CALIFORNIA
From 25-OCT-21 14:00:00 to 25-OCT-21 21:00:00 (PST-8)
Location: CEDAR GLEN
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Department of Highways

Large boulder in lane of Highway 330 at Live Oak Drive per CHP Caltrans Quickmap.

Debris Flow in SAN BERNARDINO, CALIFORNIA
From 25-OCT-21 12:00:00 to 25-OCT-21 21:00:00 (PST-8)
Location: CEDAR GLEN
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Department of Highways

Rocks on Highway 330 lanes and at least 1 large boulder reported. Heavy rainfall of 0.5 to 0.7 in 1 hour occurred in this area. Location at the highway 330 passing lane.

High Wind in SAN BERNARDINO COUNTY MOUNTAINS, CALIFORNIA
From 25-OCT-21 06:00:00 to 25-OCT-21 15:00:00 (PST-8)
Magnitude: 57.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

Gusty winds occurred across the region with mesonet Pilot Rock Truck Trail measuring peak wind gust of 66 MPH.

Heavy Rain in ORANGE, CALIFORNIA
From 25-OCT-21 00:00:00 to 26-OCT-21 00:00:00 (PST-8)
Location: TRABUCO CANYON
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

Moderate to heavy rain fell across the region. Santiago Peak reported 1.40 inches of rain in total, with a max hourly rainfall rate of one half inch.

Debris Flow in SAN BERNARDINO, CALIFORNIA
From 25-OCT-21 12:00:00 to 25-OCT-21 21:00:00 (PST-8)
Location: GREEN VLY LAKE
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Department of Highways

Rocks in both lanes on Highway 18, which has steep rocky terrain between Big Bear Dam and Snow Valley. Heavy rain of 0.4 to 0.7 inches in 1 hour occurred in the area. Caltrans and CHP reported on Quickmap.

Debris Flow in SAN BERNARDINO, CALIFORNIA
From 25-OCT-21 15:00:00 to 26-OCT-21 03:30:00 (PST-8)
Location: GLEN MARTIN
Flood cause: Heavy Rain / Burn Area
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Department of Highways

About 1000 cubic yards of debris, mud and rock removed from Highway 38 near Valley of the Falls Road with some rock slides near Mountain Home Village. This prompted the closure of the highway from Valley of the Falls Road to Sugar Pine Road from 530 pm on the 25th to 430 am on the 26th.

Debris Flow in SAN BERNARDINO, CALIFORNIA
From 25-OCT-21 12:00:00 to 26-OCT-21 00:00:00 (PST-8)
Location: FAWNSKIN
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Department of Highways

Both lanes of Highway 18 covered in mud reported at Big Bear Dam.

Heavy Rain in SAN BERNARDINO, CALIFORNIA
From 25-OCT-21 09:00:00 to 25-OCT-21 22:00:00 (PST-8)
Location: LAKE ARROWHEAD
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

Heavy rain occurred across the area with storm totals mainly 1 to 2 inches. The Lake Arrowhead area received the highest amounts, with stations reporting over 2.5 inches of rain in total. The Lytle creek and Lake Arrowhead areas received some impressive rainfall rates, some measuring near 0.85 inches of rain in one hour.

Flash Flood in SAN BERNARDINO, CALIFORNIA
From 25-OCT-21 16:00:00 to 25-OCT-21 21:00:00 (PST-8)
Location: FOREST FALLS
Flood cause: Heavy Rain / Burn Area
Property damage: 5.00K
Crop damage: 0.00K
Reported by: Department of Highways

Large amount of water flow near Potato Canyon and Oak Glen Roads, possibly on Birch Creek Road. A vehicle was swept off roadway and rescue was performed. Heavy rainfall of 0.4 to 0.6 in 1 hour occurred across the El Dorado burn scar and San Bernardino Mountains. Highway 38 was closed for several hours through the evening while Caltrans removed mud and debris from the highway. Total rainfall in the area was about 0.75 to 1.00 inch. County Public Works removed 250 cubic yards of debris from Birch Creek. Survey of the flood and debris flow was done by California Geological Survey jointly with WCM Alex Tardy.