DESERT DELUGE SURPRISE STORM'S FLASH FLOODS TRAP DRIVERS.

Byline: Ryan Oliver and Nicholas Grudin Staff Writers

While most of the Los Angeles region endured another day of 90-degree heat, fierce thunderstorms pounded the Mojave Desert late Wednesday, unleashing flash floods that forced the closure of Interstate 15 and trapped motorists in their cars in the Antelope Valley area.

One woman whose car was swept off the road and into a wash in the Antelope Valley was rescued by a Los Angeles County Fire Department helicopter crew in a dramatic scene captured on television.

The torrents of thick, muddy water severely damaged a bridge's supports on I-15 near Baker, forcing the California Highway Patrol to shut down the main artery to Las Vegas just after 9 a.m.

By late Wednesday, Interstate 15 traffic had been diverted to Interstate 40, which had one lane closed for paving, causing a 27-mile traffic jam, the California Highway Patrol said.

``Anyone going to Vegas is not going to get past Barstow,'' CHP Officer Adam Cortinas said.

The Oat Wash bridge near Zzyzx Road was expected to remain closed until noon today.

Huge clouds formed during the afternoon over the San Gabriel and San Bernardino mountain ranges that separate the Los Angeles Basin from the desert to the north.

Flash flood warnings were issued for desert areas of Los Angeles, San Bernardino and Imperial counties during the afternoon as rain poured down and lightning arced across the darkened sky.

About 15 motorists were traveling near 140th Street East and Avenue G near Edwards Air Force Base when fast-moving flood waters suddenly swirled around them.

``They're stuck on dry land with water surrounding them on both sides, so they can't get out,'' Los Angeles County Fire Inspector Edward Osorio said.

The dramatic Fire Department rescue came after a woman's car was swept off the roadway by flood waters and into a wash.

``She was in about a foot of water,'' Osorio said. ``The rescue crew touched down, ... pulled her from her vehicle and took her away in the helicopter.''

Officials at the time were also concerned about an overturned truck partially submerged in the wash near the woman's vehicle. The Fire Department's swift water rescue team searched the truck and the area around it for people, but concluded it was probably a junked vehicle.

``No one was inside,'' Osorio said. ``It looked like it must have come from the vehicle graveyard.''

Jennifer Perkins was among those who found herself stuck on Avenue G. She has been trying to get home when she was unable to cross the street because of water and deep mud.

``I've been here 27 years and I've never seen anything like this, Perkins said. ``I've seen this in Texas but never here.''

Osorio said wires had fallen down on Avenue G between 140th Street East and 170th Street East in the Antelope Valley, where the road had also been closed due to water and debris. He said evacuations were being ordered, but people were leaving voluntarily in search of higher ground.

CHP Officer Jason Peavy said a number of streets in the desert were closed off. Authorities even had to relocate their command post as heavy rain continued into the evening and threatened their original location.

``The water is moving very fast and it's really deep,'' Peavy said. ``This is extremely dangerous. ... Everything looks flat, but it's flowing. Like, the ground is flowing.''

The flash floods struck areas near Edwards Air Force Base and Lancaster about 4:30 p.m. after a lingering thunderstorm dumped more than two inches of rain in two hours.

The storm was part of a large system that hit Southern California and was also responsible for unleashing heavy rain in the San Diego area.

``It's barely moving, and that's the problem,'' said Stuard Seto with the National Weather Service.

Seto said the dry desert soil is also prone to creating flash-flood conditions.

``The rain only soaks in about a quarter of an inch and the rest is runoff,'' Seto said. ``It's pretty instantaneous.''

Staff Writer Greg Botonis and The Associated Press contributed to this report.

Ryan Oliver, [phone]

ryan.oliver(at)dailynews.com

CAPTION(S):

2 photos, map

Photo:

(1 -- color) In this photo taken from television, a Fire Department crewman helps a woman from her car to a waiting helicopter.

KABC-TV

(2 -- color) Residents of the Lancaster area walk through the flooded intersection of 140th Street East and Avenue G.

Jeff Goldwater/Staff Photographer

Map:

NORTHBOUND INTERSTATE 15 CLOSED

Staff graphic