Dry, Gusting Winds Create Quite a Stink

Dry desert winds slashed through Orange County on Tuesday, uprooting trees, blowing down power lines and causing a 30-foot pile of manure to spontaneously ignite, prompting residents of an east Irvine housing development to briefly evacuate because of smoke.

The winds set off burglar alarms that were sensitive to movement, knocked out traffic signals and forced cancellation of a hilltop ceremony to mark the start of construction on a section of roadway linking Mission Viejo and Rancho Santa Margarita.

Downed power lines blocked railroad tracks near San Juan Capistrano, delaying Amtrak trains passing through the county between San Diego and Los Angeles.

In Riverside and San Bernardino counties, the winds were strong enough in places to tip over tractor-trailer trucks. Gusts up to 50 m.p.h. forced closure of Interstate 15 between Highland Avenue and Interstate 215 in Devore.

The National Weather Service reported that wind readings in Santa Ana topped 30 m.p.h. twice Tuesday morning. But the winds were reported to be blowing even harder elsewhere in the county.

Officials at the El Toro Marine Corps Air Station said winds up to 43 m.p.h. caused a “spontaneous combustion” fire amid huge piles of horse manure on a nearby fertilizer farm.

Marine Maj. Jim McClain said the fire broke out about 3:15 a.m. near the base’s riding stables at Irvine Boulevard and Lambert Road.

The fire cast a pall of heavy smoke that blew directly into a housing development nearby. Some residents evacuated to the El Toro Marine School, he said, until the flames were extinguished about two hours later.

An Orange County Fire Department spokeswoman said there were several piles of manure at the site, some 20 to 30 feet high. She said they are owned by the Wilbur-Ellis Co., which packages the manure as fertilizer.

The hot dry winds were also blamed for a roof fire that caused $50,000 damage to a house in Yorba Linda. Burning embers from the chimney, which lacked a spark-arresting screen, ignited the roof of the house in the 4500 block of Plumosa Drive, fire officials said. About 20 Orange County firefighters were sent to quell the blaze and protect other homes from the flying embers, fire spokeswoman Kathleen Cha said.

The winds caused widespread power outages, interrupting service to about 7,400 Orange County customers of Southern California Edison Co. by mid-afternoon, said company spokesman Steve Nelson. They were among the approximately 40,000 Edison customers experiencing power outages Tuesday throughout Southern California because of the wind.

For the most part, Nelson said, the outages were confined to neighborhoods or individuals rather than widespread areas of north and central Orange County.

South County customers of San Diego Gas & Electric Co. also experienced sporadic outages, officials said. Several hundred lost power for two hours starting at 11:50 a.m. when winds blew down power lines in south San Juan Capistrano.

The lines landed across the Santa Fe Railroad tracks used by Amtrak. The tracks were blocked for about 40 minutes, setting back the trains’ schedules by about 30 minutes, a Santa Fe spokesman said.

In Mission Viejo, the planned ground-breaking ceremony for the start of the $15.5-million Oso Parkway extension was canceled because of the high winds. Plans had called for shuttling guests up to a hilltop vista to view the 1.7-mile route.

“The caterer suggested that there have been gusts up to 40 m.p.h. in the area,” said one organizer. “You just got a lot of loose dirt in the area and it would have been difficult to have any formal ceremony under the circumstances.”

Huntington Beach police officials said officers were busy answering 40 false burglar alarms set off by the winds overnight. In Anaheim, a police lieutenant said, “we got some signal lights out and stuff like that, but nothing major” in terms of damage.

And in Tustin, a tree toppled at Red Hill and Edinger avenues, blocking a lane of traffic.

Contributing to this report were Times staff writers John Kendall and Jenifer Warren in Los Angeles and Wendy Paulson in Orange County.

Santa Ana Winds

Santa Ana winds occur at all times of the year, but they are most frequent in the fall. This week the air has flowed from a high pressure area over southern Idaho and northern Utah toward a low pressure area off the Southern California coast. Since the air moving from the high pressure area is relatively cool, the Santa Ana winds have not brought particularly hot temperatures.

Coastal Zone

The coast is one of the warmest areas since the air is compressed down to sea level and it has the highest density and temperature. Smog and dust particles are blown out to sea.

Effects Of The Wind

The wind can cause widespread damage, including downed trees, power poles and the spreading of brush fires.

Mountain Compression

The air is compressed as it moves down through the mountains surrounding the Los Angeles Basin toward sea level. As the density of the air increases, its temperature goes up and its humidity goes down. This helps create the hot dry conditions of the Santa Anas.

High Pressure Area

Air moving in a clockwise motion over Idaho/Utah is drawn toward a low pressure area off the Southern California coast.

Dry Desert Air

The dry desert air removes much of the moisture as the air flows from the high pressure area to the low pressure area.

Heating Of The Air

As a general guide, air warms about 5.5 degrees F for every 1,000 feet it drops. As the air moves from the Great Basin region--elevation about 4,500 feet--toward the coast, the air will heat up by at least 25 degrees.

Canyons And Passes

The canyons and passes surrounding the Los Angeles basin are well suited for increasing the speed of the Santa Ana winds. The Santa Anas tend to be from the north-northeast and the canyons are mainly oriented in the same direction. As the air enters the canyons, it is squeezed much as a stream whose banks have narrowed.. As the winds are funneled they accelerate, often causing 2 to 3 times the wind speed in the canyons than in the basin.