Farmers Prepare to Protect Crops as Cold Wave Nears : Weather: Citrus and avocados are most susceptible to chill that may drop temperatures into the upper 20s by Monday night.

Farmers in the Santa Clara Valley were bracing Friday for the first cold snap of the season as a brisk storm system out of the Gulf of Alaska advanced on Ventura County.

Temperatures are expected to drop into the upper 20s in isolated pockets of Santa Paula, Fillmore and Piru on Tuesday morning, said National Weather Service meteorologist Terry Schaeffer.

Growers on Friday were warming up wind machines, filling smudge pots and putting workers on call for a possible all-nighter to ward off frost damage to cold-sensitive crops.

Orchards laden with delicate citrus and avocados in the Santa Clara Valley and Moorpark would be most susceptible to damage, said Dave Buettner, the county’s chief deputy agricultural commissioner.

“Citrus is our biggest concern because there is more fruit on the trees at this time of year than other crops,” he said.

A low-pressure system will begin cooling off the county today, Schaeffer said. Highs today and tomorrow will be in the 60s throughout the county, he said, and lows will be in the 30s in the inland valleys and the low 40s near the coast.

There is a slight chance of sprinkles late Sunday, when clouds move into the area, Schaeffer said. The coldest weather from the front will arrive Monday night, when lows dip into the upper 20s in valleys and low 30s along the coast, he said.

Steve Fox, orchard manager for Fillmore-based Pro-Ag, said that making preparations for frosts and freezes is nothing new.

“We go through it every year around this time,” said Fox, who oversees 2,500 acres of lemons, oranges and avocados around the county. “We just make sure the wind machines are working.”

Rob Brokaw, whose family owns a 600-acre avocado ranch near Santa Paula, said workers have been busy replacing batteries and lubricating the motors in wind machines in preparation for the cold weather.

Wind machines are used to raise temperatures in the groves by circulating air. They also keep frost from settling on crops.

Growers typically expect the danger of frost to begin about Nov. 15, Brokaw said.

“We make sure the smudge pots are ready to go with a good supply of oil,” he said. “We have helicopters on standby to substitute for wind machines in areas where we don’t have them.”

Buettner said the threat of damage to citrus is not serious unless temperatures drop below 28 degrees for an extended period. Avocados need slightly warmer temperatures, he said.

But Schaeffer said frost will probably occur only in isolated spots and would not last long. Temperatures will begin warming Tuesday, with a return to clear skies and seasonal highs in the low 70s expected by Thanksgiving Day, he said.