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Flash Flood Warnings and Watches Have Expired (Update 5)

By News Staff Member
Saturday, August 30, 2008

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Update - Saturday 6 p.m.

The Flash Flood Warnings and Watches have expired. The threat for flash flooding has ended.

Update - Saturday 3:15 p.m.

The National Weather Service has issued a Flash Flood Warning for west central San Bernardino County until 5:45 p.m. The areas in this warning include, but are not limited to Big Bear Lake, Big Bear City, and Onyx Peak.

At 2:45 p.m., Doppler radar indicated flash flooding from thunderstorms over the warned area. Radar indicates rainfall rates of one to two inches per hour may be expected with the heavier storms, along with small hail.

Debris flows issuing from basins burned by the Slide Fire can impact Highways 330, and any other roads within the burned area, particularly where they cross burned drainages.

Update - Saturday 2:15 p.m.

The National Weather Service has issued a Flash Flood Warning for west central San Bernardino County until 5 p.m.

At 2:06 p.m., Doppler radar indicated heavy rain from a thunderstorm over the area between Apple Valley and Lucerne Valley, along Highway 18. The storm is almost stationary. Rainfall rates in excess of an inch per hour and small hail are likely with this storm area. The storm producing flash flooding will otherwise remain over mainly rural areas of San Bernardino County.

The National Weather Service reminds motorists to "Turn around, don't drown!"

The Flash Flood Warning for extreme south central San Bernardino County and west central Riverside County remains in effect until 4:30 p.m. for the Forest Falls to Cabazon regions. (See 1:45 p.m. update.)

Update - Saturday 1:45 p.m.

The National Weather Service has issued a Flash Flood Warning for extreme south central San Bernardino County and west central Riverside County until 4:30 p.m.

At 1:22 p.m., Doppler radar indicated developing thunderstorms from near Forest Falls and developing south from Forest Falls to Banning and Cabazon. The storms will be moving slowly south at 10 miles per hour and may move over the Esperanza burn area of 2006. The storms may also move south to the Idyllwild and Pine Cove areas by 4:30 p.m.

The watersheds burned by the Esperanza fire will be particularly susceptible to flash floods and debris flows during rainstorms. The parts of the communities of Beaumont and Banning that are located adjacent to the burned area, including Smith Canyon and Potrero Creek, may be affected by these events.

In addition, roads may be impacted by these storms where they cross burned drainages. These roads include, but are not limited to, Beaumont Avenue, Circle C Road, Castille Canyon Road, Highland Springs Avenue, Old Banning Idyllwild Road, Shirleon Drive, Poppet Flats Road, State Highway 243, Cryer Drive, and Mount Edna Road.

Update - Saturday 7:30 a.m.

A Flash Flood Watch remains in effect though this evening. Scattered thunderstorms with heavy rainfall will develop over the mountains and deserts. Flash flooding is possible along streams in the mountains and washes and low-lying terrain in the deserts, especially below the mountain slopes. The flash flood threat will diminish around sunset.

In areas where fires have been in recent years, mudslides will be a threat during heavy rains.

Remember, "Turn Around, Don't Drown".

Original - Friday, 11:25 p.m.

Monsoonal moisture will move in from the southeast tonight and Saturday. By early afternoon, the atmospheric profile should become favorable for scattered thunderstorms with heavy rainfall in the mountains and adjacent deserts of extreme southwestern California. This will result in a risk of flash flooding.

The National Weather Service has issued a Flash Flood Watch for a portion of southwest California, including Apple and Lucerne Valleys; Coachella Valley; San Diego County deserts; and San Bernardino, Riverside, and San Diego County mountains. The watch is in effect from 11 a.m. until 7 p.m. Saturday.

Scattered thunderstorms with heavy rainfall will develop over the mountains and deserts mainly Saturday afternoon. Flash flooding is possible along streams in the mountains and washes and low-lying terrain in the deserts, especially immediately below the mountain slopes. The flash flood threat will diminish by around sunset Saturday.

A Flash Flood Watch means that conditions may develop that lead to flash flooding. Flash flooding is a very dangerous situation. The National Weather Service advises you should monitor later forecasts and be prepared to take action should flash flood warnings be issued.