Santa Anas

viscius winds from the east

Thu Jun 28, 2007 | 07:25am

THE SUN COMES UP bright that day. It is a Friday-June 17, 1859. There is a little breeze from the northeast, a clear sky, and the promise of a warm day. The morning temperatures are normal, 75-to-80 degrees, with an offshore breeze that prevents the ocean from having a cooling effect.

By noon, people begin to notice something unusual is happening. The temperature has quickly risen to almost 100 degrees and the mountain breeze is becoming stronger and stronger. About 1 pm a heavy blast of hot air sweeps through the Goleta Valley from the direction of Santa Ynez Peak, driving even the hardiest into the shelter of their homes and filling them with terror; they think the end of the world has come.

The superheated air continues to pour down on the coast for the next hour. By 2 pm the temperature is an incredible 133 degrees! Many of the people take refuge behind the thick walls of Daniel Hill’s adobe, who is owner of Rancho La Goleta, where they pray fervently for the oppressive heat to be lifted.

For the next three hours the temperature hovers at 130 degrees; by 5 pm it has cooled off only slightly, to 122 degrees. The inhabitants wonder if this will ever come to an end. Then suddenly, as fast as it has come, the hot breeze dies and a cool marine breeze washes over the land. By 7 pm the temperature is a comfortable 77 degrees and the half-baked citizens emerge from their houses to see what damage has occurred.

“Birds had plummeted dead from the sky; others had flown into wells seeking cooler air and drowned,” says Walker Tompkins, describing the event in his book, Goleta the Good Land. “A fisherman in a rowboat made it in to the Goleta sandspit with his face and arms blistered as if he had been exposed to a blast furnace.”

“Calves, rabbits and cattle died on their feet,” adds a government report. “Fruit fell from trees to the ground, scorched on the windward side; all vegetable gardens were ruined.”

Did this really happen? There are no doubters among those who are here in Santa Barbara on Wednesday, June 27th, 1990, when the Painted Cave Fire starts and the temperature a sizzling 108 degrees.

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“The seasons here usually change slowly, some say not at all,” Russ Spencer writes in an article in the News & Review in 1986. “But Santa Ana winds can turn a brisk, 60-degree winter day into something resembling the inside of a clothes dryer.”

There are times in the mountains when the wind seems to blow incessantly. In the morning, at first light, the breeze begins to kick up. As the sun warms the mountain slopes the air begins to heat, and to expand, rising upward. Cooler marine air moves across the valley floor, a soft wind that replaces the ascending air, and it, too, moves up the mountain wall. By afternoon the columns of air tower over the mountains, once again cooling, and condensing to form billowing cumulus clouds, a picturesque backdrop for the city.

In the evening the wind reverses itself, the clouds disappearing, the cooler, heavier air falling from the sky, down canyon, and into the sea, off-shore breezes that fill the sails of the small boats just off the edge of the harbor.

But these winds do not threaten. It is the cruel and capricious santa ana, or sundowner, which does – causing the severe fire weather which determines whether a fire will lay down like a docile dog or whip up into a frenzy of uncontrollable fury.

These devil winds are known by many names-simoon, santa ana or sundowner in Southern California; chinook in Colorado; ghibli in the Middle East; zonda in the Argentinian Andes. It is a condition initiated by conditions a thousand miles away, where high pressure on the western slope of the Rocky Mountains forces the dry, hot desert air toward the Pacific Coast.

These viscious winds can reach speeds of from 20 to 90 miles per hour and last for 2-to-3 days. They occur most often in August, September, and October, at the end of the long, waterless summer, when the chaparral is at its most vulnerable. Under such conditions the chaparral can explode like a bomb, burning through the mountains at a rate of four-to-six square miles an hour, an amount equivalent to about 4 million gallons of gasoline.

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The santa ana wind is born in the Great Western Basin, an area between the Rockies and the Sierras, when high pressure systems of warm air build up there. When a zone of low pressure develops near the Pacific coast, this mass of warm air will begin to move westward towards the Pacific Ocean, eventually reaching very high temperatures by the time it descends on the Southern California.

It is in the nature, or the physics, of wind that this occurs. When it is warmed, air rises, and as it does cooler air slides across the surface of the earth to fill the void left by this rising air. As this air moves across the land we feel it as wind. The speed of this current often increases when traveling from a place of high elevation to a lower one, as is the case when it moves from the Great Basin to the coast.

Once generated, the santa ana winds swoop out of the desert, often without warning, howling through canyons and mountains, spilling through the coastal passes and funneling into Southern California along several main channels. The volume of air being carried toward the sea is phenomenal, and the velocities attained can reach gale force in minutes. Powerfully hot and dry, they are capable of fashioning a major firestorm from what might have only become a small brush fire.

According to the Glossary of Meteorology published in 1959 by the American Meteorological Society, a santa ana is “a hot, dry desert wind generated from the northeast or east, especially in the pass and river valleys of Southern California, where it is further modified as a mountain-gap wind.”

Is a santa ana the same as a sundowner?

Definitely not says Gary Ryan, who is a meteorologist for the National Weather Service in Santa Maria. “They differ in several ways,” he says. “The sundowner is a localized phenonmenon while the santa ana generally affects the entire region.

“The santa ana also draws most of its heat from high-pressure systems over Nevada and Utah,” he adds, “while the sundowner pulls its heat from the other side of the Santa Ynez mountain range.”

Part of the answer, again, is in the nature of wind.

When it reaches a barrier, such as the Santa Ynez Mountains, the air rises as it goes over the mountains, cooling somewhat in the process. Once over the mountain crest, this cooler air then tumbles down the other side and is warmed by compression as it reaches lower altitudes.

This compressive pressure cooks the air, raising its temperature as much as 5 degrees for every 1,000 feet in elevation it drops, often causing temperatures 15-to-20 degrees hotter in Santa Barbara than in the local mountains.

When santa ana conditions occur, the wind that reaches the Santa Ynez Valley is already blistering hot. It can then become a sundowner as it is superheated on the north slopes of the Santa Ynez Mountains. By early afternoon the air begins to force its way up and over the mountains, and by dusk, or sundown, the hot downcanyon winds begin to blow into town, typically lasting until about 11 pm to midnight, when cooler marine air moves in.

Whether called santa ana, sundowner, simoon or foehn, descriptions of these winds have been around for more than a hundred years. Newspaper accounts mentioning santa ana winds first appear in the 1880s. Some believe the name stems from an Indian word-santanta-or something similar, meaning devil wind. Others argue Spanish explorers who were blasted by unusually hot winds coming in from Santa Ana Canyon have named it. Still others contend that it stems from the Mexican General Antonio Lopez de Santa Ana, whose cavalry stirred up clouds of dust during military campaigns such as the one which crushed Texans at the Alamo in 1836.

Or perhaps it is simply due to the explanation given by A.J. Wilson, the city manager for the town of Santa Ana. “Santa Ana just happens to be the oldest town around here,” he says with a shrug, “and there wasn’t any place else to name the thing after.”

“City of the Santa Anas” isn’t something that the local residents are proud of. In 1901, after a particularly disastrous fire fueled by these winds, and plenty of negative publicity, the Chamber of Commerce tries in vain to have the santa ana winds renamed, citing undue fears which they are afraid will hurt business.

Whatever its name its characteristics are truly devil-like; it is a wind whose affects are not limited to hot furnace-like blasts of wind, low humidities, and fire-prone conditions.

The dry air can irritate lung tissue and nasal passages, and is extremely serious for those with emphysema. The dust it kicks up can add to the woes of those with allergies.

“It gives fine hair an uncontrollable life of its own,” News and Review writer Russ Spencer adds, “and turns curly hair into something resembling a Brillo pad.

“The skin gets flaky and itchy. Socks stick together and powerlines crackle and spit in the conductive air. People in bars up and down State Street toast in delirious glory to their new found ability to drink five beers and not go potty.”

It can even cause tempers to flare.

“There is a long history of experience, particularly in Europe, that intense dry winds tend to affect the degree of irritability,” says clinical professor of psychology at UCLA Medical Center Charles William Wahl. “For 200 to 300 years if someone committed a murder during the wind called a foehn it was considered partial exculpation. In Egypt any contract signed during the khamsin is not binding, and if a crime is committed the courts take the wind into consideration.

“I think we see a similar phenomenon in our own santa ana winds. The major change is a massive drop in the humidity. During these periods of the santa ana my patients describe to me larger feelings of irritability and irrascibility.”

Wahl and C.D. Mason, an Associate Professor of Psychology at USC, both agree that the santa ana may affect arson behavior as well. “I think perhaps not in terms of mood,” says Wahl, “but if you are an arsonist this is the best time. Everything is tinder dry and the winds can fan the flames into a large and gratifying result for the arsonist.”

“If a guy emotionally needs to see a big fire he’ll get it when the winds blow,” Mason also notes. “The arsonist is a person who has a lot of suppressed power needs. Usually, he is a person who’s not successful in life.

“It can be a symbolic expression of power. It makes loud noises. Now the guy who sets a fire or acts angrily because of the wind, you might say, is identifying with it. He is going towards this power stimulus.”

Occasionally, these winds are actually blessed. Their ability to clear out smog and make island views crisply spectacular is phenomenal. But that is little consolation on summer days when temperatures regularly reach the 90s in the backcountry. It is these winds which will determine how quickly a wildfire will spread, how difficult it will be to contain and how much damage will do done.

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