Low 20s Predicted for Tonight : Growers Struggle to Avert Damage

San Diego avocado and strawberry growers are bracing for possible crop damage caused by temperatures that weather forecasters say will dip into the low 20s tonight.

Despite the recent cold snap--Tuesday night’s temperatures were expected to fall to the high 20s--growers have reported no damage to flowers and avocado groves, which were devastated by freezing weather last year.

But, by Wednesday night--with Arctic air that is moving down from the Gulf of Alaska expected to bring lows of 22 or 23 degrees to inland valleys--the results “could look like someone took a flame thrower through the groves,” said Fallbrook grove manager Pat Murphy.

Resorting to New Methods

Wind machines, which stir the air and help to moderate the temperatures, have been operating in Fallbrook and Pauma Valley, and other growers are counting on extra irrigation to protect their groves from frost damage.

Growers have also resorted to new methods to protect their crops.

Warren Currier, executive secretary of the Escondido-based Avocado Growers Assn., said many growers are heeding new studies that show copper-based sprays kill ice-nucleating bacteria and lower the freezing temperature of the avocado leaves by a couple of degrees.

“A lot more growers this year have put copper on their groves in one form or another,” Currier said, “but that won’t do much good if we get a hard freeze.”

National Weather Service forecaster Wilbur Shigehara predicted that little crop damage would occur from Tuesday night’s low temperatures because of a cloud cover that was expected to move into the inland valleys by 10 p.m. Tuesday-night lows of 29 to 30 degrees in the inland valleys were predicted. A frost advisory was issued for those areas.

Although highs in the orchard areas are expected to reach 47 to 53 degrees during the day, they are expected to dip into the mid- to low-20s during the evening. Forecasters have issued a freeze warning for tonight.

The coast will also remain uncustomarily cold. A low of 38 degrees Monday night at Lindbergh Field fell only one degree short of the record low for that date. The record was set last year when the mercury dipped to 37 at the airport, according to Weather Service statistics.

Temperatures in all areas of the county are expected to drop even lower tonight. The coastal strip will stay chilly, in the 31-to-40-degree range, and temperatures in the mountains are expected to plummet to 14 to 22 degrees tonight, bringing the possibility of more snow.

Agricultural experts say it takes a number of days of freezing and near-freezing weather to take its toll on the crops.

Hoping It’s Quick

“The time you see serious crop damage is when there’s a couple days’ stretch of really cold weather,” said Wendy Deitrick of the San Diego County Farm Bureau. “We’re hoping we won’t see that.”

Murphy said it is a “matter of both time and temperature. We can only hope that the freeze, if it comes, doesn’t last long enough to do permanent damage.”

Growers are hoping to be spared from the damage caused last year at this time, when a five-day cold snap ruined 30% of the San Diego County avocado crop and wiped out the lucrative strawberry crop for the second year in a row.

Times staff writer Terry Rather contributed to this story.