For much of last winter an isolated, intense snow squall showed up on Internet radar over Woodstock, and appeared to linger for hours – even days – in one place.
This summer, the same isolated location seemed to be pelted regularly by a strong thunderstorm.
That location, it turns out, is right where the 10 Spruce Mountain wind turbines stand.
“We do pick them up on radar,” said Margaret Curtis, a meteorologist with the National Weather Service in Gray. “Our goal is to bounce the radar pulse off raindrops, but there are other things out there it can bounce off too, including wind turbines.”
Those “other things” are called “ground clutter.” But usually such clutter, which can include tall buildings, has a different look from storm clouds.
“Wind turbines can be a little bit tricky, because they do move,” said Curtis. “The turbine blades themselves spin, so they end up looking like a thunderstorm.”
The radar pulse sent out from Gray is aimed up at an angle of one-half of a degree.
“Around Bryant Pond, the beam is only at about 1,500 to 1,600 feet, so that could hit the tops of mountains,” she said. “But by the time you get up north of Bethel, even to Newry, it’s already at 3,000 feet.”
Mt. Washington, because of its height, shows up in Gray even though it is much farther west.
Curtis said the Gray radar will also sometimes pick up wind towers in Waldo County.
In addition to turning turbine blades, the beam can also pick up other moving objects.
“On a clear night, sometimes we’ll see bugs, sometimes we’ll see migrating birds,” said Curtis.
She said the Gray radar technology was recently upgraded to send out two beams, which provide more information – but also more clutter to sort out.
“We have to learn where all the stuff is so we can filter it out in the future,” she said.
But from a personal recreational standpoint, Curtis said, she wishes a constant snow squall over the Woodstock area was the real thing. “As a Mt. Abram skier, I wish it was still snowing there.”