Monsoonal moisture moved into Southern California on August 15th and resulted in numerous showers and thunderstorms across the region. Heavy rain fell in the San Diego County Mountains on August 15th, and became more widespread on August 16th and 17th. Mount Laguna picked up 3.20 inches of rainfall on August 17th. Numerous areas of flash flooding and debris flows were reported throughout Southern California, particularly in the Riverside and San Bernardino County mountain areas. A landspout tornado was reported in the Anza Valley associated with a severe thunderstorm. No injuries or major damages were reported.

Tornado in RIVERSIDE, CALIFORNIA
From 16-AUG-18 14:00:00 to 16-AUG-18 14:30:00 (PST-8)
Location: ANZA
Tornado F-scale: EF0
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Public reports of a landspout tornado northwest of Anza, CA. No injuries or damages were reported.

Debris Flow in RIVERSIDE, CALIFORNIA
From 17-AUG-18 15:00:00 to 17-AUG-18 21:00:00 (PST-8)
Location: MOUNTAIN CENTER
Flood cause: Heavy Rain / Burn Area
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Department of Highways

California Department of Transportation reported that there were dozens of small debris flows in and around the Cranston Fire burn scar on August 15th  but highway 74 was proactively closed based on NWS warnings. On August 17th, there was a large debris flow up to 5 feet deep in the Lake Hemet Campground area from Hurkey Creek. Again highway 74 was closed about 2 hours in advanced based on NWS briefings and the actual Flash Flood Warning.  Very large boulders were reported to have traveled downstream on the upper Hurkey Creek near Fleming Ranch. Evacuations were in order at Hurkey Creek Campground and Sheriff was on site monitoring the potential based on NWS briefings. Video of the debris flow was captured. A storm survey was conducted by NWS following the debris flow. No injuries or major damages reported from this event. Rain gauges in the area reported 1-1.5 inches of rainfall near the Cranston Fire burn scar. Evacuations of the small communities near the Cranston Fire burn scar were put into place on August 15th in anticipation of the heavy rainfall and potential for flash flooding and debris flows.

Flash Flood in RIVERSIDE, CALIFORNIA
From 16-AUG-18 15:00:00 to 16-AUG-18 18:00:00 (PST-8)
Location: CHERRY VLY
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Law Enforcement

CHP reported that Brookside Avenue and Highland Springs Avenue was flooded out on both sides of the road from the heavy rain.

Debris Flow in SAN BERNARDINO, CALIFORNIA
From 16-AUG-18 14:00:00 to 16-AUG-18 20:00:00 (PST-8)
Location: FOREST FALLS
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Public and Fire Radio reported that Valley of the Falls Drive was closed due to a debris flow.

Flash Flood in SAN BERNARDINO, CALIFORNIA
From 16-AUG-18 15:00:00 to 16-AUG-18 18:00:00 (PST-8)
Location: LUCERNE VLY
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Law Enforcement

CHP reported that water and mud flooded the entire roadway on Highway 247 at Locus Ave. No damages or injuries reported.

Flash Flood in SAN BERNARDINO, CALIFORNIA
From 16-AUG-18 16:00:00 to 16-AUG-18 19:00:00 (PST-8)
Location: DESERT SPGS
Flood cause: Heavy Rain
Property damage: 5.00K
Crop damage: 0.00K
Reported by: Law Enforcement

CHP reported that Highway 18 near Johnston Road was flooded. A vehicle went off the road in that area into a pothole and became flooded with water. Persons in the vehicle made it out okay, but some damage to the vehicle from the water.

Thunderstorm Wind in SAN BERNARDINO, CALIFORNIA
From 16-AUG-18 14:50:00 to 16-AUG-18 14:55:00 (PST-8)
Location: APPLE VLY ARPT
Magnitude: 40.00 MG
Property damage: 0.10K
Crop damage: 0.00K
Reported by: Mesonet

Apple Valley mesonet (gntc1) reported a 40 knot thunderstorm wind gust at approximately 2:50 PM PST on August 16th.

Heavy Rain in SAN BERNARDINO, CALIFORNIA
From 16-AUG-18 16:00:00 to 16-AUG-18 18:00:00 (PST-8)
Location: WRIGHTWOOD
Reported by: Trained Spotter

Two spotters reported heavy rainfall in Wrightwood -- approximately 1 inch per hour rainfall rate. Moderate flooding was reported.

Heavy Rain in SAN BERNARDINO, CALIFORNIA
From 16-AUG-18 17:00:00 to 16-AUG-18 17:35:00 (PST-8)
Location: WRIGHTWOOD
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

A trained spotter reported 1.14 inches of rainfall in 35 minutes.

Debris Flow in SAN BERNARDINO, CALIFORNIA
From 16-AUG-18 17:00:00 to 16-AUG-18 19:00:00 (PST-8)
Location: WRIGHTWOOD
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Public reported a debris flow at the Sheep Creek Wash in Wrightwood on Lone Pine Canyon Road. The road was closed down for a few hours to clean up the debris flow.

Debris Flow in RIVERSIDE, CALIFORNIA
From 17-AUG-18 16:00:00 to 17-AUG-18 19:00:00 (PST-8)
Location: MOUNTAIN CENTER
Flood cause: Heavy Rain / Burn Area
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Sheriff reported that a major debris flow occurred on Highway 74 near the Cranston Fire  burn scar. No injuries or damages were reported.

Debris Flow in RIVERSIDE, CALIFORNIA
From 17-AUG-18 15:00:00 to 17-AUG-18 18:00:00 (PST-8)
Location: PALM DESERT
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Law Enforcement

CHP reported boulders across the roadway on Highway 74 in Pinyon Pines near the fire station. No injuries or damages were reported.

Debris Flow in SAN BERNARDINO, CALIFORNIA
From 17-AUG-18 14:00:00 to 17-AUG-18 17:00:00 (PST-8)
Location: BALDWIN LAKE
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Law Enforcement

CHP reported a rock/dirt/mud slide along Highway 38 between Onyx Peak and the town of Sugarloaf. Law enforcement indicated that the road was covered in rocks. No injuries or damages reported.