SANTA BARBARA, CALIF., DEC. 28 -- Jordan Mo arose on Christmas Eve to find a color photo on page one of the local newspaper showing Russ Satow, an avocado rancher in Carpinteria, squatting in what the accompanying caption described as "a winter wonderland of ice" covering his trees.

Mo called the newspaper. "It may be a wonderland to you, but it's a horrorland to the rancher," she said tartly. Then she went off to check on the condition of her own damaged avocados on 14 hilly and frosty acres north of here.

Meanwhile, in an orange grove near Fresno, 200 miles northeast of here, Keith Nilmeier was assessing the results of a desperate battle with the weather.

Nilmeier had spent a sleepless night trying to save his 30 acres of navel oranges by running precious 68-degree well water through his orchards and then using wind machines in an attempt to heat the air. He also had burned 200 tons of dried peach pits in bonfires scattered around the orchard.

Nothing worked. Although Nilmeier is a resourceful farmer who had salvaged his orange crop a year earlier when the thermometer dipped into the low 20s, he was helpless against temperatures that fell to 15 degrees. He lost his entire crop, valued at $100,000.

His plight was typical of citrus and vegetable growers in the three San Joaquin Valley counties of Fresno, Kern and Tulare, which are requesting federal and state disaster relief. Agricultural officials in these counties today estimated losses of $288 million in the California navel orange crop, the "eating orange" most frequently found in eastern stores.

"I do not believe there is a lemon or orange in the San Joaquin Valley," said Fresno farmer Don Laux.

Officials here are uncertain of the extent of damage to Valencias, the principal juice orange, which is picked later. As far as consumers are concerned, there are ample supplies of juice oranges in Florida and other states.

But for farmers in northern and central California, the "Arctic express" that hurtled through the West during Christmas week was a disaster of great magnitude. Nilmeier, a citrus grower for 18 years, said of the cold wave, "It's a frost I've never seen."

According to Dennis Plann, deputy agricultural commissioner for Fresno County, Nilmeier would not have seen such a frost even if he had been ranching for a century. County records show that current temperatures are the coldest in many parts of the San Joaquin Valley of any time since the 1880s.

The cold has killed an estimated 40 percent of trees less than two years old in the valley. A new cold wave is expected this weekend, and agriculture officials said a repeat of last week's temperatures could threaten even mature trees.

"We are not concerned with the crop anymore," Nilmeier said. "We're trying to save the trees."

Despite his losses, Nilmeier considers himself relatively fortunate in comparison with some farmers. He has low debt and a diversified farming operation that includes production of peaches and grapes.

Mo also is more fortunate than many farmers. Her avocados are grown on sloping hills where the elevation ranges from 500 to 750 feet. While she lost avocados at the low end of her property, those on the higher hills, where it was slightly warmer, survived with the aid of wind machines.

In a good year, Mo makes $70,000 on her crop. This year, she estimates that she will make $20,000 at most and could lose money if damage to her trees proves more extensive than early inspection indicates.

Hardest hit of all are farm workers and packers, many of whom lost their jobs the day after Christmas. Joel Nelson of California Citrus Mutual, a grower's organization, said 15,000 people have been laid off because the state's 70 produce packing houses have nothing for them to do.

Industry officials say it is too early to assess the impact of the California freeze on national food prices beyond a certain increase and probable scarcity of navel oranges. Only about 20 percent of the navel crop was picked before the freeze. A 40-pound carton of oranges now sells for $22, two to three times last year's price.

California avocado growers have lost approximately 20 percent of their crop, according to the California Agricultural Statistics Service. The state's farmers also have suffered heavy losses in strawberries, artichokes, broccoli, cauliflower, lettuce, celery and fresh flowers.

Nonetheless, Agriculture Department analysts in Washington clung to a forecast that, even before the freeze, estimated that food prices would increase by 2 to 5 percent in 1991. A department report observed that the severe cold in California "caused extensive damage to the citrus and vegetable crops" but noted that similar crops in Texas and Arizona escaped serious damage.

In agriculture, one farmer's disaster tends to be another's opportunity, and growers in other southwestern states as well as in slightly warmer Southern California may benefit from the freeze.

"As one farmer here said, they will make money on somebody else's misfortune," said Bob Perkins, manager of the Riverside County Farm Bureau. "The price of remaining fruit will rise because of damage in the Central Valley."

Apple growers in California also may benefit because the cold weather induced dormancy in apple trees that is likely to be beneficial.

But for most California farmers, the freeze was the latest unhappy chapter in a devastating weather cycle. Some citrus and avocado trees that succumbed this week had been damaged by the statewide drought, the longest in a half-century. Emil Low of the California Food and Agriculture Department said the freeze had "made things worse, because frost dries everything out a lot."

The area of high atmospheric pressure that has brought in the Arctic cold also has played a significant role in keeping Pacific storms from reaching California, which now faces a fifth consecutive abnormally dry year. In some areas, such as Santa Barbara, only one-fourth of an inch of rain has fallen since Sept. 1, less than one-eighth of the normal total.

For urban dwellers, particularly in the normally smoggy Los Angeles basin, the cold winds have lowered air pollution levels and produced bright, clear days of the kind enjoyed in the region decades ago before smog became a serious problem.

That is no comfort to farmers on the brink such as Nilmeier and Mo, who said they are hoping that the next freeze will not be as severe as the last.