Windfarms blamed for disrupting weather forecasts

Wind farms have been blamed for disrupting the lives of birds, bats and, most recently, the land-bound sage grouse. But now the massive spinning blades affixed to towers 200 feet high have also been blamed for affecting weather preictions.

Published: 7:00AM BST 27 Aug 2009

Wind turbines can appear on Doppler radar, which is used by weathermen, like a violent storm or even a tornado.
The phenomenon has affected several National Weather Service radar sites in different parts of America, even leading to a false tornado alert near Dodge City, Kansas, in the heart of Tornado Alley. In Des Moines, Iowa, the weather service received a frantic warning from an emergency worker who had access to Doppler radar images.

The alert was quickly called off in Kansas and meteorologists calmed the emergency worker down, but with enough wind turbines going up last year to power more than 6 million homes and a major push toward alternative energy, more false alerts seem inevitable.
Radar software can easily filter out buildings, cell towers and mountain ridges on radar screens. But because weather radar seeks motion to warn of storms, there's no way to filter out the spinning blades.
Dave Zaff, science and operations officer with the National Weather Service office in Buffalo, New York, said that 99 per cent of the time the farms will not pose a problem.
But in a worse-case scenario, a forecaster could disregard a real storm for turbine interference, he said.
"If you take a glance and then all of the sudden you see red, you might issue an incorrect warning as a result," he said.