MELISSA BLOCK, host:
From rain dances to cloud-seeding, farmers have tried to control the weather for centuries. Now some of California's biggest peach and plum farmers are trying to stop destructive spring hailstorms. Sash Khokha of member station KQED reports they're trying to blast the ice right out of the clouds.
SASHA KHOKHA: Farmer John Diepersloot sells his fruit to stores like Whole Foods and Safeway. He says one bad spring hailstorm can destroy his crop, knocking delicate peach blossoms off the trees or leaving pock marks on his tender baby plums.
Mr. JOHN DIEPERSLOOT (Peach and Plum Farmer, California): We'll lose market share when our fruit is marked or scarred. The market still demands perfect fruit.
KHOKHA: So Diepersloot decided to install a weather radar on top of his rooftop. When it shows a storm approaching, he knows it's time to put on his protective earmuffs.
Mr. DIEPERSLOOT: Here we go. One click, and then it'll start going.
KHOKHA: He first turns on cylinders of natural gas. A spark plug ignites the gas, sending a huge blast through a 20-foot-high metal cannon pointed at the sky.
(Soundbite of explosion)
KHOKHA: The idea is that the sonic boom from this hail cannon will send shock waves up into the clouds to rattle the moisture and prevent chunks of ice from forming. The theory is the water will then turn into slush or rain.
Mr. CHARLES KNIGHT (National Center for Atmospheric Research): Well, I hope it works for them.
(Soundbite of laughter)
Mr. KNIGHT: I sincerely hope it works for them, but I'm also sure that nobody will ever know whether it does or not.
KHOKHA: Charles Knight is a leading hail expert with the National Center for Atmospheric Research in Boulder. He says there's no way to prove whether or not hail cannons actually stop ice chunks from forming. Who knows if a storm cloud blasted by the cannons would've produced rain anyway instead of pellets of hail? Knight says people have tried to battle hail for centuries.
In some parts of France, they ring church bells. In Italy, farmers have shot exploding rockets into clouds. And in the Soviet Union, they tried to seed clouds with artillery shells. None of these techniques have ever proved to work against hail. But California farmers have faced rising hail insurance costs in recent years, and some say paying $40-60,000 for a hail cannon is a better bet. Harry Andis(ph), farm advisor for the University of California, says the cannon probably just make farmers feel better about storms.
Mr. HARRY ANDIS (University of California): It's hard to outwit Mother Nature. There's really nothing that we've come up with at this point that we can outwit her. So a hail cannon probably makes the grower feel good, like he's doing something. Whether it's actually doing some good is still unknown.
KHOKHA: One proven effect of the cannons: they aggravate neighbors. The blasts can be heard up to 12 miles away. When farmers first started firing them off near Fresno, patrons in a local diner saw their coffee cups shaking. They thought they were in the middle of a powerful earthquake.
For NPR News, I'm Sasha Khokha in Fresno.