WASHINGTON — A new state-of-the-art radar system on the Washington coast will make it easier for meteorologists to track heavy weather coming off the Pacific Ocean, as some scientists say the intensity of winter storms and waves pounding the Northwest shore is increasing.
Until now, the Washington state coastline has been the only coastal area in the continental United States with no weather radar coverage.
The region's storms more than rival the hurricanes and nor'easters elsewhere in the nation. A storm on Columbus Day in 1962, considered the most intense non-tropical storm to hit the U.S. in a century, had sustained winds along the coast of 150 mph, with gusts to 180.
"If it hit today it would cause Katrina-like damage," said Cliff Mass, a professor of atmospheric sciences at the University of Washington. "We get some of the most intense storms in the world. We have no radar."
The National Weather Service is expected to announce the site for the new radar installation in coming months, likely in Grays Harbor County, on the central Washington coast. It should be operational by 2012, said Brad Colman, the meteorologist in charge of the weather service's Seattle office.
"We are moving as quickly as we can," Colman said.
As the National Weather Service proceeds with the design and construction of the new radar, scientists at Oregon State University's department of geosciences, using data from buoys far offshore, have concluded that wave heights and the power of winter storms have been on the upswing over the past nearly 30 years.
Studies using data from a lightship stationed off the southwest coast of Britain and buoys off the U.S. Atlantic coast have reached similar conclusions.
"While these increases are most likely due to Earth's changing climate, uncertainty remains as to whether they are the product of human-induced greenhouse warming or represent variations to natural multi-decadal climate cycles," says a report scheduled for publication in the journal Coastal Engineering.
The study found that median waves off the Northwest coast are more than a foot higher than they were 30 years ago. The very largest waves are 8 to 10 feet higher. During the largest storm, offshore waves can be more than 45 feet tall.
"It's pretty wild out there," said Peter Ruggiero, an assistant professor at Oregon State and one of the authors of the study.
The size of the bigger waves is increasing faster than the size of smaller waves is, Ruggiero said, and the size of the waves off Washington state is growing faster than those off Oregon. He also said the increased size of the waves was more of a threat to coastal areas than the ongoing rise in ocean levels was.
Ruggiero said that he and the other researchers who worked on the study were sensitive to criticism that the findings were based on only 30 years of data.
"We would like longer records," he said, "but without a doubt we see a trend in the data."
Damage from violent, dangerous storms blowing in from the north Pacific isn't limited to the Northwest coastline.
In December 2007, a storm with winds that gusted on the coast to nearly 140 mph brought torrential rains to parts of western Washington state. Bremerton, across Puget Sound from Seattle, received a record 10 inches of rain in 24 hours. Extensive flooding in Lewis County, south of Olympia, closed Interstate 5, the major north-south highway on the West Coast, for three days. Fourteen people were killed and property damage was estimated at more than $1 billion.
Since 1953, there have been 41 presidential disaster declarations involving Washington state, most of them for flooding and high winds. Washington state was tied for 15th among 59 states and territories in the number of disaster declarations from 1953 to 2008.
The University of Washington's Mass and others said better radar coverage on the coast could have helped forecasters issue warnings, especially flood warnings for inland areas such as those during the 2007 storm.
A congressionally requested report released last spring said the precise track and intensity of storms coming off the Pacific were often "difficult to analyze and predict" with existing radar.
There are currently two major weather radar stations in the Northwest, on Camano Island in Puget Sound north of Seattle and in Portland, Ore. Those radars are 20 to 25 years old.
The Olympic Mountains block the Camano Island radar's view of the Washington coast. The Coast Range interferes with the Portland radar's view of the northern Oregon and southern Washington coasts.
"Virtually no radar coverage is available over the ocean, where the majority of western Washington's weather originates," last year's report found.
Forecasters use satellite and buoy data along with numerical models to track storms, but satellites don't provide the same detail as the Doppler radar that's planned for the Washington coast.
Mass said using satellite data was like just examining a sick person, while the Doppler radar was like a CAT scan, which can look inside.
The new coastal radar has a maximum range of about 250 miles and will provide fine details of storms 150 miles out in the Pacific.
"This radar will improve forecasting not only for the coast, but for Puget Sound and even central and eastern Washington," Mass said.
The National Weather Service's Colman said the new radar wouldn't solve all the forecasting problems in the region.
"Some of the expectations are a little unrealistic," Colman said. "But it will certainly help."
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