Study Designed to Measure Ice Storm Severity in Oklahoma

An electric utility official and a state meteorologist in Oklahoma have developed a system to measure the severity of an ice storm that may help people better prepare.

Sid Sperry, an official with the Oklahoma Association of Electric Cooperatives, and Steve Piltz, the meteorologist in charge at the Tulsa National Weather Service forecast office, created the “Sperry-Piltz Utility Ice Damage Index.”

Researchers at the Oklahoma Climatological Survey office in Norman found evidence of warming at the surface by studying statewide average winter December through February temperatures since 1896. Another report indicated warming at the surface and lower portions in the atmosphere across most of the nation and in particular the northern hemisphere.

The hypothesis that a warming climate could lead to more frequent ice storms meshes with ideas of conditions needed to form freezing rain.

Although there’s no solid proof of a connection between the two, research suggests the possibility that significant ice storms will continue to affect Oklahoma.

Damage potential is categorized in five levels by ice thickness, wind speed and direction, and temperatures for the storm period.

“By being able to predict three or four days in advance not only the likely path and footprint of an ice storm, but also accurately estimating the total amount of ice that could potentially accumulate on power lines, and knowing well ahead of time the forecast wind speeds and temperatures, we can better prepare our electric line crews for the potential damage that they may be dealing with,” Sperry said.

He said they can know well ahead of time where to send additional repair crews, where ice accumulations will be the most severe, and predict with a high degree of accuracy the amount of damage to a utility system.

Since 2000, there have been six storms in Oklahoma bringing ice of more than an inch. With those have come deaths, injuries and more than $1 billion in property damage.

More than two dozen deaths were blamed on a December 2007 ice storm that knocked out electric power to more than 640,000 homes and businesses across the state, making it the worst power outage in the state’s history.

Information from: The Oklahoman, www.newsok.com