- The Washington Times - Thursday, December 6, 2001

Skiers who make the trek to Seven Springs Resort in Champion, Pa., typically prepare for any kind of weather.A few, though, tackle the slopes with trepidation after scanning the latest wind-chill reports, based on an index that purports to tell just how cold it really feels outside.
Dick Barron, who oversees the resort's slopes and keeps skiers updated on the latest wind-chill warnings, says the reports sometimes paint an unrealistic portrait that hurts business.
"It's played too strongly in the media," says Mr. Barron, a 31-year veteran of the Pennsylvania resort.
He will have less to complain about now, thanks to a change at the National Weather Service (NWS) that makes its wind-chill readings less ominous and, it says, more accurate.
The service, part of the National Oceanic and Atmospheric Administration in Silver Spring, revamped its wind-chill index last month, creating a more helpful portrait of the wintry conditions facing us.
The old method, created in 1945 by Antarctic explorers, was introduced to the public by the National Weather Service in 1973.
Under the retired scale, a 20-degree day featuring 15-mph wind gusts would yield a wind-chill factor of 4 degrees below zero. Under the new chart, the wind chill would be a less intimidating 6 degrees above zero.
The new scale follows this formula: Wind chill (degrees Fahrenheit) = 35.74 + 0.6215T - 35.75(V0.16) + 0.4275T(V0.16), where T = ambient air temperature in Fahrenheit and V = wind speed in mph.
The old formula read as: Wind chill (Fahrenheit) = 91.4 + 0.0817 (3.71 V0.5 + 5.81 - 0.25V) (T - 91.4).
The wind-chill index is a measure of how fast the body loses heat. It measures thermometer readings combined with how strong the wind is gusting. Winter-sport enthusiasts monitor the numbers to dress properly for the outdoors. Parents check them to make sure their little ones go into the elements prepared for winter's worst.
Mark Tew, chairman of the NWS' Joint Action Group for Temperature Indexes, says work began on the new system a year ago.
However, the project has been on the minds of NWS members for nearly a decade, Mr. Tew says.
"The previous index was based on 1945 research," Mr. Tew says from NWS headquarters. "It was innovative for its day, but we wanted to apply the latest in technology to bring the wind-chill index into the 21st century."
Under the new measurement, the U.S. and Canadian governments, the latter measuring degrees in Celsius, will share a wind-chill index for the first time.

To create the new standard, Mr. Tew's group pooled the disparate talents of an assortment of experts culled from the Department of Transportation, the U.S. Department of Agriculture and members of academia.
Also in the mix were representatives of Environment Canada, our northern neighbor's version of the National Weather Service.
The researchers began by studying all the existing ways to calculate wind chills and choosing two that both were simple in design and used wind and temperature as their key elements. One came from Environment Canada; the other was created by researchers at Indiana University Purdue University Indianapolis.
The group tested six men and six women during the summer at Toronto's Defense and Civil Institute of Environmental Medicine.
The focus was on human skin and how it loses heat when it faces chilling temperatures.
"The new model is a facial model," Mr. Tew says. "That's the most exposed portion of the body."
In the old system, measurements were taken at a height of 33 feet, the average height of an anemometer, which measures wind speed. Researchers lowered that model to 5 feet, approximate face level, and studied the theory of heat transfer, the loss of heat from the body to its surroundings.
That, combined with extensive use of computer modeling to calculate skin-tissue resistance under cold conditions, unavailable when the original system was created, helped forge the current wind-chill equation.
"When the wind blows, there's a little layer of heat out from the surface of the face, like a shield, a protectant," Mr. Tew says. "The wind removes that heat barrier."
Twelve volunteers walked for 90 minutes on a treadmill with temperatures as low as 14 degrees Fahrenheit and winds upward of 18 mph.
Sensors were placed at various points on their faces their noses, cheeks and chins. The sensors measured drops in skin temperature and heat loss as the wind and cold levels were manipulated.
The new system also offers a frostbite advisory missing in the previous wind-chill index system.
"Now, we can tell people when wind chill becomes a danger," Mr. Tew says.
The new system warns that a person will suffer frostbite if he or she stays outside for 30 minutes in 5-degree temperature with winds at 19 mph or more. The same person will get frostbite in 10 minutes in minus-10 degree weather if the winds are whipping at 37 mph or more.
Mr. Tew acknowledges the imperfections of the old system.
"The old index did overstate the wind-chill effect. Maybe that was a good thing," he says. "They dressed appropriately.
"We don't want people to get a false sense of security," he says of fears that the public will see the new system as warmer and not pay attention to the figures as much as in the past. "We've highlighted the danger areas, and we want people to use them as a guide."
Not everyone was warmed by news of a new wind-chill index.
Joel N. Myers, founder, chief executive and president of AccuWeather, scolds the NWS for sticking to a system widely acknowledged as inaccurate.
"The old wind chill was flawed. They knew it was flawed, but they kept using it, overwarning people," he says.
AccuWeather, a commercial weather service in State College, Pa., that provides forecasting services to nearly 20,000 clients, offers its own wind-chill measurement, known as RealFeel Temperature. The service can be accessed at www.accuweather.com.
RealFeel figures are updated hourly, as are related data for more than 300,000 other locations worldwide.
AccuWeather's system, which debuted in 1998, takes into account temperature, wind speed, humidity, solar intensity, precipitation and elevation, among other key factors.
"It runs the complete gamut of all conditions from very cold to very hot," Mr. Myers says.
For a 30-degree Fahrenheit day with 10 mph winds, the old NWS system would render a wind chill of 16 degrees. The new NWS system would show 21 degrees and RealFeel 20 degrees.
Under the NWS wind-chill measure, Mr. Myers argues, a December day of 25 degrees and 10 mph winds would be read the same as a day in April with the same figures, though people would perceive them quite differently, he says.
Regardless of the disparities, Mr. Myers says wind-chill measurements can save lives, given the severity of harsh weather systems.
"Real extremes of weather are more dangerous to your health than tornadoes, hurricanes and lightning," he says.
Doug Hill, chief meteorologist at WJLA-TV, says the NWS' new system "goes a long way" toward improving the existing scale. Wind levels at 33 feet can be far more dramatic than they are at 5 feet, so that change alone should present a more accurate calculation.
Now, the media should do their part to use the information wisely.
"The way wind chill has been presented by the media it's gotten hyped," he says, blasting broadcasters who bark out scary figures to alarm the public.
Mr. Hill understands Mr. Myers' arguments about the system, but he says the new system deserves a chance.
"I've come down on the side that I'm gonna give it a shot over the winter," he says.
Besides, he says, "We're not talking about Alaska it's Washington."
Winter weather has yet to arrive in the area, but the lull won't last long.
In October, the NWS released its winter preview, which anticipated an unpredictable season, one much cooler than the mild winters of the late 1990s.
As for Mr. Barron at Seven Springs, he will keep posting the wind-chill factor on his daily reports for skiers, but he doesn't expect too much to change.
"You wear face masks, goggles, you're fine. It's just as pleasurable as any other day," he says of the resort's patrons. "They come here dressed for winter."


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