Sticky Stuff in Rain Was Desert Dust and Alkali

Sticky powder that fell with the rain in Riverside, San Bernardino and other Southern California communities was merely wind-borne alkali and desert dust, the South Coast Air Quality Management District concluded Thursday.

Jim Birakos, district deputy director, said laboratory analysis of the stuff that spotted car finishes and other surfaces late Wednesday showed that it was not acidic and apparently not harmful to humans. He recommended hosing off autos to avoid scratching the paint.

Birakos said there were reports that “a burst of storms” lifted a huge volume of alkali from the bed of Owens Dry Lake in the Mojave Desert and carried it aloft.

Winds were gusting to 60 m.p.h. in some parts of Southern California on Wednesday, at one point kicking up so much dust that California 138 in the Antelope Valley had to be closed because of near-zero visibility.

Formed ‘Star Burst Patterns’

When the dust and alkali particles finally fell to the ground with the rains late in the day, Birakos said, they formed “star-burst patterns.” Close inspection showed that the particles--colored orange, yellow and white--were “a natural substance,” he said.

Winds abated throughout the area on Thursday and were expected to decrease even more today and Saturday. But they were strong enough early Thursday morning to tear an 8-by-40-foot section of roof from a Von’s supermarket in the 600 block of Foothill Boulevard in La Canada Flintridge. Water pipes ruptured, causing extensive damage to stock.

The high in downtown Los Angeles on Thursday was 74. The overnight low was 56. And it was dry, with relative humidity ranging from 13% to 23%.

With high pressure building over the Pacific Northwest and with a low-pressure system over Arizona and New Mexico, a mild Santa Ana pattern was developing to bring Southern California locally gusty winds out of the north and northeast through tonight.

The weather should warm a bit, offering a pleasant weekend with the high in downtown Los Angeles near 76 today and near 80 on Saturday.

The San Francisco Bay area experienced some record-breaking warm weather Thursday as the result of winds from inland. San Francisco had a high of 77, which broke the previous record for the date of 76, set in 1881. That made San Francisco two degrees hotter than Palm Springs.

Records were also broken in Sacramento (where it was 75), San Jose (74), Oakland (81) and Santa Rosa (78).

In the Southland, the mountains should have variable cloudiness through the weekend, with highs ranging from 44 to 54.

The northern deserts are expected to have highs from 56 to 66 today and Saturday. The southern deserts will warm up to 78 today and 83 on Saturday.

A small-craft advisory will be in effect through today for inner waters below coastal canyons from Point Conception to Point Vicente because of winds gusting 20 to 30 knots. In the outer waters, there will be a small-craft advisory for all of Southern California because of similar winds and combined seas of 7 to 13 feet.