Windmills, Hail Guns, & Sweet Agers
"Using the windmills has helped them lose only one peach crop in the last 12 years. The magic numbers for freeze at McCleod Farms is 17 degrees F for a short period and 24 degrees F for 12 hours or more. The warm air from the windmills and burning hay prevents cold air and frost from settling on the bloom.
After escaping late spring freezes, a major concern is hail. To combat hail, the McCleods have installed a ‘hail gun’. The hail gun saturates the air above the orchards with high decibel sound waves that break up hail storms. During high risk times, they closely monitor Doppler radar via a computer link. When conditions are right, they zap the air with ear-splitting sounds."
You can read more on this 21st century operation at the Southeast Farm Press site here.