Gary Ball, an independent citrus and avocado farmer from Fillmore, says that helicopters are his most valuable weapon against frost. The use of helicopters for frost abatement in Southern California started about ten years ago and has become more extensive in the past four years. It is quickly becoming one of the most effective ways to protect avocadoes, citrus, and strawberries, against frost destruction.

One of the helicopter companies used for frost control by farmers is Air Cavalry, Inc., based at Van Nuys Airport. The main participants in Air Cavalry’s frost program are, it’s owner and commander Albert Cito II, an ex army captain who served four years in Vietnam. Wayne Richardson, the energetic chief pilot who is known amongst his colleagues for flying off the handle. Chuck Davey, a funny guy who laughs so much that one can’t help but laugh along with him. Mario Fatigati, a cool, pleasant, smooth talking Italian-American, always looking for a deal, who runs a mobile pet grooming service on the side. These pilots are the frost warriors awaiting the farmer’s word to lift-off within minutes and eradicate an invisible but deadly enemy. The degree of collaboration between the farmer and the pilot is precise, “They [the farmers] know exactly where they are all the time, like a military organization they keep you programmed ahead of time so that you’re ready to come out at a moment’s notice and raise that temperature if necessary, and raising that temperature one degree can be the difference between a failure and a saved crop,” says Al Cito.

Terrain, orientation, wind, moisture, and vegetation are all conducive to frost formation. The type of terrain where crops are located is important. Most of the groves are in gently rolling terrain in the Santa Paula and Ojai valleys. “The rolling nature of the land causes the low pocket to collect supercooled air, and it’s in that low pocket that the problem occurs,” says Al Cito. Gary Ball, a citrus and avocado farmer out in Fillmore, says that each one of these elements can increase frost twofold. For instance, Gary’s field faces Southward, and has 5 to 6 nights of frost per year, versus fields facing Northward which have between 10 to 15 nights of frost per year. In addition, clear windless nights where the temperatures fall below freezing are ideal for frost formation. Because of this, Gary and other farmers have removed their wind shields, mostly composed of eucalyptus trees. Other factors like dry ground and weeds also increase frost.

The purpose of the helicopter in this process is twofold. First, the rotor downwash moves the air which stirs the leaves. Creating friction, which generates heat. Second, during the night, the heat which is trapped by the Earth during the day rises as the ground cools. This results in a layer of warmer air above the cooler air covering the ground. When you have an increase in temperature with height, this is called an inversion. The helicopter’s function is to push down that inversion into the cooler air on the ground.

Since the warm air will tend to rise, this effect will last for about an hour, depending on how cold the night gets. The helicopter then has to repeat this process. It flies above the orchards in strait patterns. Unless a field is clearly separated by wires or trees that define a clear border, only a single helicopter can be used per field, to prevent a collision. During very cold nights the pilots will literally continue to fly until they run out of fuel. The fuel for the operation is stored in 55 gallon drums with hand pumps. This is done simply because during the stretch of time it would take the helicopter to refuel at Van Nuys, the farmer could loose his crop. Al Cito stresses the importance of this service: “Now, think about this, when a strawberry farmer looses his crop, he’s lost a lot. He’s lost a whole years worth of work, and he’s not going to make anything when comes harvest time. When an orchard grower or a grovier looses his crop, he’s not only lost this year’s crop, he’s lost his ability to make a crop because those trees have to be mature before they bare fruit.”

In conjunction with helicopters, farmers use diesel powered windmills, smudge pots, and microsprinklers. These are not as efficient as a helicopter because they are fixed, require constant upkeep, and are labor intensive. Gary Ball says that the helicopter is not cheap, but it is only used for a few days out of the year. The windmill’s height does not always coincide with the height of the warm air they are to use, and the horizontal wind they create cannot get past some of the trees. The helicopter on the other hand has the ability to change altitude and find the inversion (warmer air) and feed the air to each individual tree. Smudge pots are cheap to purchase, costly to operate, and very polluting. Chuck says that it’s like flying through fog when they are on. The use of water sprinklers to keep the Earth moist is a a useful means of retaining the heat within the soil. Because water freezes slower, moist soil will freeze at a slower rate than dry soil.

The comparative figures are interesting. A helicopter covers 100 acres for $250 an hour while a windmill only covers 10 and costs 15-20000 Dollars plus fuel and maintenance. Gary says he would need eight machines. You need about 40 smudge pots per acre at one gallon per hour of diesel at 0.50-1.00 Dollar per gallon.

A typical frost alert scenario might begin with Gary, after checking his preliminary weather report at 10:30 and final report at 18:30, he deduces that frost might be a factor that evening. He calls Wayne around 16:00. Wayne then calls Chuck to tell him that he will be on standby for the night. Chuck comes in to the Air Cavalry at around 18:00. He puts on a turtleneck, long johns with a rear trap door, and apres ski boots. Then he dons his bright, polyester filled, orange overalls “so if I crash they can locate me,” he says. He goes out to preflight the helicopter and then returns to await the farmers call giving him the go-ahead. Sometimes the go-ahead never comes. In that case the pilots do not get paid their hourly rates but a night standby fee. Chuck says that it’s cheap insurance considering the unpredictability of frost. Some farmers will call them before midnight if they feel the frost threat has subsided, some will not. In which case, Chuck often end up sleeping on the floor.

The call comes in. The helicopter is preflighted and ready. Chuck jumps in, straps himself tight, cranks it, the rotors are turning, he lifts off. He arrives at the field 30 to 40 minutes later. The farmer says the temperature is decreasing fast. Chuck takes off and hovers fifteen feet above the trees, not too low so as not to destroy the foliage. “It’s like mowing your little lawn, all night long,” says Chuck wearily about the constant, straight line, hovering pattern above the trees. The farmer communicates with the pilot through a handheld transceiver. He tells Chuck to divert to another area of the field which is getting colder. Gary or his foreman positions flares or bright lanterns to direct the pilot. Each area has a thermometer which the farmer can gauge, since the whole field does not remain at the same temperature. Chuck looks at the fuel gauge. Its getting low on fuel. Time to land. On the ground, he refuels from the 55 gallon drums tanks the Air Cav. brought, and Gary brings him coffee, “it was dark out there, dark and cold,” Chuck said. The night is getting colder, so he has about an hour to rest before he must go up again to slap that warm air down on those trees. This can go on till sunrise and can get very boring and tiring. There are also many inherent dangers like having an engine failure in the dark with few spaces to land, or hitting wires.

Mario had a package deal when he flew over a field on a hillside with wires going up on each side of the hill and crossing in the middle of the field, like an “H” pattern. In addition, there were wind machines blowing air at each corner of the field, which made flying all the more fun. When he finally had to refuel, he had to drop into an enclosure of high eucalyptus trees where the fuel drums were placed, and had engine failures on landing and takeoff from the fuel site. At dawn he had barely enough gas left to make it back to Van Nuys, after having flown over six hours. “It sounds funny now, it wasn’t funny then,” Chuck mentioned later.

There is no doubt that there are certain dangers in this type of helicopter flying, but none that a conscientious pilot can’t overcome. From what we have seen, the helicopter is not just a luxury in the fight against frost, but an efficient and economically viable means of protecting crops.

© 1989. All Rights Reserved