Hail cannon seemingly helps cranberry farmer

A hail cannon sits at a central Wisconsin cranberry farm and may prevent hail storms

CRANMOOR - Hail storms can be a farmer's worst nightmare.

Some in Door County experienced that first-hand just last month, when hail damaged cherry and apple crops

A cranberry bog owner in Central Wisconsin, though, thinks he may have found a way to prevent such damage.

When thunderstorms approach the Potter and Son cranberry farm west of Wisconsin Rapids, owners turn to their cannon.

First you hear a thud, which steadily gets louder.

And before long, powerful blasts are coming every few seconds.

The source is what's called a hail cannon, a contraption that produces controlled explosions to supposedly prevent hail.

Owner Mel Potter says he used to lose up to 10 percent of his crop annually from hail damage before installing his first cannon in 1995.

But since then, it's been a different story.

"I'm absolutely positive that it works because for almost 20 years, we haven't had any hail. We used to pretty near every year have a little bit," said Potter.

Hail is often consider to becoming "damaging" once it reaches about an inch in diameter - the size at which the parent storm is considered severe.

But even small hail can damage a cranberry bog.

Hail formation relies on updrafts in thunderstorms keeping frozen raindrops in the sky.

The drops circulate in the updrafts, and keep getting bigger.

Before long, they get too heavy and fall out of the storm.

In principle, the focused blasts from this cannon interrupt that process, and in turn protect a roughly half-mile radius of fields around a single cannon.

It takes about 13 blasts for the hail cannon to get to full volume.

The cost to operate the cannon is about a thousand dollars per year in fuel.

That is a fraction of the amount that losses of even 10 percent of Potter's annual crop would be.

But what's really going on here?

Is the cannon really impacting the storms, or has Potter just had a string of good luck over the past 19 years?

Correlation does not always mean causation, and in the 20 years that Jeff Last has been at the Green Bay National Weather Service, he says the office also hasn't seen any hail damage.

And they don't have a hail cannon.

Said Last, "We're talking about thunderstorms many miles in diameter, Any man-made device having an effect that would reduce large hail... If a storm's going to produce large hail, it's going to produce large hail, regardless of what man-made devices are out there."

No matter what the case may be, if there's a storm moving through the area, Mel Potter will be blasting away with his cannon.