Monsoon moisture from the southeast, as well as the remnants of Tropical Storm Ivo, set off thunderstorms along and east of a line from Big Bear, south to Tecate, Mexico each afternoon/evening. These storms produced very heavy rain, with over 2 inches measured at many mountain and desert locations including Agua Caliente, Borrego Springs, Pine Hills and La Quinta. Borrego Springs and the southern Coachella Valley were the hardest hit areas for flooding on the 23rd and 25th, with several roads closed due to heavy water flow and washouts with mud and debris. Several cars were nearly submerged in flooded roadways in La Quinta and Indio, stranding drivers. The Indio gauge along the Whitewater Storm Channel experienced a sharp rise from near zero to 1080 cfs over approximately 30 minutes on the afternoon of the 25th. Highway 62 near Desert Hot Springs was also affected with very a very wide and deep area of flowing water, rocks and debris. Highway S22 near Borrego Springs suffered significant road damage and road closures for up to 24 hours.

Flash Flood in RIVERSIDE, CALIFORNIA
From 25-AUG-13 14:00:00 to 25-AUG-13 16:00:00 (PST-8)
Location: RANCHO MIRAGE
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

A spotter reported 1.24 inches of rain fell in 35 minutes near the intersection of Highway 111 and Indian Trail Road in Rancho Mirage, resulting in 1 foot of water in the roadway at the gutters. The Century Theatre at The River in Rancho Mirage also evacuated movie-goers due to flooding.

Flash Flood in RIVERSIDE, CALIFORNIA
From 25-AUG-13 16:00:00 to 25-AUG-13 18:00:00 (PST-8)
Location: BONNIE BELL
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Water, debris and boulders were flowing across Highway 62 just north of North Indian Canyon Drive. The area flowing across the highway is 40 feet wide and 6 feet deep.

Flash Flood in SAN DIEGO, CALIFORNIA
From 25-AUG-13 15:00:00 to 25-AUG-13 17:00:00 (PST-8)
Location: BORREGO SPGS ARPT
Flood cause: Heavy Rain
Property damage: 100.00K
Crop damage: 0.00K
Reported by: County Official

Borrego Springs Valley Road from Rango Way to Tilting T Road, Borrego Springs Road (S-33) from San Pablo to Yaqui Pass, and S-22 (Montezuma grade) were closed all of Sunday night due to debris and flooding. Mobile homes were flooded in the DeAnza Mobile Home Park. A spotter reported 18 inches of water over Highway S-2 at Vallecito Creek. Several low water crossings were also flooded with swiftly moving water over Highway S-22 between Borrego Springs and Ranchita, including Yukie Road. Numerous large boulders blocked the roadway, with other debris and running water in the roadway. Around this time, 3.35 inches of rain fell in two hours near Ranchita.

Flash Flood in SAN DIEGO, CALIFORNIA
From 25-AUG-13 17:00:00 to 25-AUG-13 19:00:00 (PST-8)
Location: AGUA CALIENTE SPGS
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Significant mud and debris was reported at the Agua Caliente Springs airport...and the Agua Caliente county park. A spotter reported 18 inches of water over highway S-2, near Canebrake. Shortly before, an NWS rain gauge near Agua Caliente Springs recorded 2.05 inches of rain in 30 minutes.

Flash Flood in RIVERSIDE, CALIFORNIA
From 23-AUG-13 15:00:00 to 23-AUG-13 16:00:00 (PST-8)
Location: PALM SPGS
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Other Federal Agency

The USGS stream gage at Palm Canyon Creek reported a 2.7 ft. rise between 1500 and 1600 PST, with an estimated flow of 363 cfs.

Flash Flood in RIVERSIDE, CALIFORNIA
From 23-AUG-13 17:00:00 to 23-AUG-13 18:00:00 (PST-8)
Location: SAN JUAN HOT SPGS
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Newspaper

Araby Road was closed at Palm Canyon Wash due to moving water and mud covering the roadway.

Flash Flood in RIVERSIDE, CALIFORNIA
From 25-AUG-13 14:00:00 to 25-AUG-13 15:00:00 (PST-8)
Location: PALM DESERT
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Law Enforcement

The intersection of Paisano Road and Cholla Way was washed out and impassable with flash flooding occurring.

Flash Flood in RIVERSIDE, CALIFORNIA
From 25-AUG-13 14:00:00 to 25-AUG-13 16:00:00 (PST-8)
Location: LA QUINTA
Flood cause: Heavy Rain
Property damage: 120.00K
Crop damage: 0.00K
Reported by: Broadcast Media

Significant water flow on Whitewater storm channel through la quinta was reported by the Coachella Valley Water District. The water was contained in channel, but flowed through some golf courses. Waist deep water was reported along some roadways, stalling and nearly submerging several vehicles. A driver noted that the flooding came on quickly, in about 20-20 minutes.

Flash Flood in RIVERSIDE, CALIFORNIA
From 25-AUG-13 14:00:00 to 25-AUG-13 17:00:00 (PST-8)
Location: PALM DESERT
Flood cause: Heavy Rain
Property damage: 200.00K
Crop damage: 0.00K
Reported by: Broadcast Media

Widespread flooding was reported in the areas of Indio, Indian Wells and Palm Desert due to very heavy rain. The storm channels in Palm Desert, many of which flow through the middle of golf courses, were running swiftly. Large rocks up to soccer ball size and water up to 2 feet deep covered Fred Waring Drive in Indian Wells, stranding one vehicle. The intersections of Avenues 48 and 49 with Monroe and Madison Streets were both covered with a foot or more of water, stalling at least 3 vehicles.