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Taking a Bite Out of Winter Travel Hazards

parked snowplows, covered in snow
(©UCAR, photo by Carlye Calvin.)

When winter weather's at its worst, snow and ice often spell danger on the roads and in the air. Researchers can't make these threats disappear, but they can make a difference that contributes to fewer transportation delays and greater travel safety.

At NCAR, advances in detection and prediction of snow and ice are being translated into tools for decision making. These tools help the people responsible for our transportation systems decide when, where, and how to respond to whatever winter weather has to offer. Here's a look at some efforts aimed at taming winter travel hazards.

Moving down the highway

Motor vehicle accidents involving bad weather—largely ice and snow—claim the lives of more than 6,000 Americans and injure almost half a million more each year. Highway officials typically weigh complex and often conflicting reports about weather forecasts, road conditions, and traffic from a battery of computer monitors—an imperfect technique informally known as "swivel chair integration."

Web display, Treatment Selector MDSS displays like this one will help maintenance crews decide how best to keep roads clear of ice and snow. Click here or on the image for a larger version.  

To improve that process, scientists at NCAR and several other institutions are collaborating to develop a comprehensive national program for road weather research, development, and applications.

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Winter's Wallop
Our Research: Smart Highways
A New Tool to Help Keep U.S. Roads Ice-
  and Snow-Free

One example is a Web-based experimental system sponsored by the Federal Highway Administration that promises to save lives, cut costs, and help keep drivers on the move. The Maintenance Decision Support System uses software to balance weather information from several computer models and deliver road-specific advice to maintenance crews: whether or not to plow, how much deicing chemical to apply per mile, and when to reapply treatment. The software program also considers whether a surface might refreeze after a brief warm-up.

Air travel and ice: on the ground

close-up of jet engine encrusted in ice Heavy freezing drizzle iced up this jet engine as the pilot waited for takeoff. The white swirl is a design feature. (Photo courtesy United Airlines.)

The bulid-up of ice on aircraft waiting for takeoff can be a serious safety hazard. Only 0.8 millimeters of ice on top of a wing—a coating thinner than a compact disk—increases drag and reduces airplane lift by 25%. Deicing, however, is an expensive proposition: with deicing fluids costing $2-4 per gallon, airlines can spend tens of thousands of dollars in a single day, with additional costs for flight cancellations and delays.

In a multiyear research program, NCAR scientists have been developing a data gathering and display system to aid airlines in making deicing decisions.

The deicing component of the Weather Support to Decision Making (WSDM) system uses Doppler radar, surface weather data, and snow gauges to predict winter weather up to 30 minutes ahead of time. That lead time allows airlines to deice more efficiently and keep flights on schedule. WSDM data are displayed in a color-coded, user-friendly format that can be easily read by pilots and other non-meteorologists.

Web display, Treatment Selector About five inches in diameter, the Hotplate uses two plates warmed by electrical heaters. It measures rates of rain- or snowfall by how much power is needed to evaporate precipitation on the upper plate while keeping its surface temperature constant. The second plate, positioned directly under the evaporating plate and heated to the same temperature as the top, factors out cooling from the wind.  

After nearly a decade of testing, a commercial prototype of WSDM is operating at Denver International Airport and, as of mid-December, at Minneapolis-St. Paul. The system is also being considered for deployment at New York's three major airports.

Another instrument that can operate alone or as part of WSDM was developed by NCAR researchers and colleagues at the Desert Research Institute to calculate real-time rates of snow, rain, and other types of precipitation. The Federal Aviation Administration provided funding for the research as part of the effort to improve ground deicing of aircraft. The Hotplate™ Total Precipitation Sensor uses no moving parts and requires no maintenance during a storm, so it can be placed in difficult-to-access areas. At airports it can provide accurate readings of snowfall rates at locations, such as runways, where aircraft waiting to take off are most at risk of experiencing dangerous snow and ice build-up. As part of NCAR's program of technology transfer, the Hotplate is now manufactured by Yankee Environmental Systems.

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Reducing the Tab for Deicing
New Research Helps Protect Airplanes
  from Drizzle

Heavy freezing drizzle —masquerading as harmless light drizzle—has cost airlines as much as $2 million in engine damage in a single storm as jets have waited for takeoff. The latest version of WSDM includes a real-time system for more accurate detection of freezing drizzle, helping airlines take action to protect delicate fan blades on jet engines.


Air travel and ice: in the air

The buildup of ice on airplanes in flight is a major wintertime hazard for small and commuter planes and has been a contributing factor in a number of fatal accidents. Protecting planes from in-flight icing is therefore a high priority for the aviation community. But detecting the treacherous regions in clouds that can produce ice on aircraft wings remains a work in progress. NCAR researchers collaborate with NASA, the National Weather Service, and other agencies in the search for new tools and techniques to help pilots steer clear of this danger.

ice buildup on leading edge of wing on small aircplane
Ice on the wing of the NASA Twin Otter research aircraft. (Photo courtesy NASA Glenn Research Center.)

One result of this research was the launch of a new forecasting tool for airlines in 2002. The Current Icing Potential (CIP) provides pilots with an online display of high-precision maps that identifies areas of potential aircraft icing produced by cloud drops, freezing rain, and drizzle. It draws on surface observations, numerical models, satellite and radar data, lightning observations, and pilot reports. A companion product that is based solely on numerical model output, the Forecast Icing Potential (FIP), provides outlooks of icing conditions up to 12 hours in advance.

NCAR researchers tested a new radar system in March 2004 that has the potential to pinpoint ice-prone cloud droplets. The radar's precision in locating icing threats will hopefully soon contribute to better warning systems for pilots.

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New Radar System May Help Airplanes Avoid
  In-Flight Icing

Airlines Get New Tools to Avoid In-Flight Icing
Prospecting for Ice
Our Research: Airplane Icing

The system, known as S-Polka, combines two existing radars that use different wavelengths. By studying the differences between the images that are reflected back to each radar, scientists hope to find tiny water droplets that are difficult to distinguish using either radar alone.

Sharpening forecaster skills

home page for MetEd Web site
Click here or on the image to go to the MetEd Web site.

Professional forecasters seeking to hone their skills in predicting hazardous winter weather conditions often turn to UOP for classroom or online instruction through the Cooperative Program for Operational Meteorology, Education and Training.

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Our Research: A Training Ground for

MetEd: Winter Weather Topics

For wintertime aviation forecasting, COMET's MetEd Web site offers online training specifically geared to icing type and severity—and other aviation weather topics. As with all the MetEd training materials, you don't have to be a professional to explore the site's engaging, interactive offerings.





posted February 2005; updated December 2005






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