Meteorologist Cliff Mass examines Pacific Northwest weather in his new book

No, Seattle isn't the rainiest city.

But the Pacific Northwest can lay claim to many other meteorological milestones:

• Mount Baker ski area shattered the world snowfall record with 1,140 inches during the winter of 1998-99.

• The foggiest spot in the nation is Cape Disappointment, on Washington's Long Beach Peninsula.

• The Olympic Mountains lead the continental U.S. in annual rainfall, with a soggy average of more than 180 inches.

"I can go on and on," says Cliff Mass, who reels off weather nuggets like a baseball fan reciting stats.

But the University of Washington meteorologist's voice takes on a hushed tone when he gets to this one: The country's most ferocious nontropical cyclone in a century pummeled the Northwest coast with winds gusting close to 200 mph on Columbus Day, 1962. The storm flattened vast swaths of forest, toppled statues and smashed more than 50,000 buildings.

"I wish I had been here," says Mass, who was a weather-obsessed 10-year-old living on Long Island at the time. "We're talking category 3 hurricane-type winds."

Pause.

"It would have been great."

Mass recounts the story of that October storm on the first page of his new book, "The Weather of the Pacific Northwest." In an area marked by extremes, the Columbus Day storm is the ultimate example of what nature can hurl at the region.

But in this corner of the world, even everyday patterns are intriguing, Mass says. "We probably have the most extreme gradients in weather of any place in the U.S.," he says. Rain forest and rain shadow. Desert and glacier. All can be found in the Northwest, often only a few miles apart.

The book draws on the most current science to explain why. It's written in a clear, simple style aimed at the layman, but with enough sophistication and detail to satisfy serious weather afficionados. Colorful photos and graphics liven the text and make technical concepts easier to grasp.

"I'm hoping people will come away with a very practical understanding of our local weather phenomena," he says.

Working with Carl Sagan

Mass is one of Washington's biggest weather celebrities, on a par with television meteorologists. Many people plan their weekends based on his Friday forecasts on radio station KUOW-FM (94.9). The station's lines light up whenever he fields questions, and he's quoted widely in the press when the weather turns foul or forecasts are bungled.

The book grew out of his radio experiences and all the questions he's fielded over the years. It's also part of his commitment to communicate science to the public, something he learned from Carl Sagan.

The legendary astronomer and science popularizer was Mass' mentor when Mass was an undergraduate at Cornell University. Sagan helped Mass write his first scientific paper, on a weather prediction model for Mars. Mass, who had always been fascinated by extreme weather, was headed to graduate school at Massachusetts Institute of Technology when Sagan convinced him the University of Washington was the nation's top school for meteorology.

"Carl is why I'm here," says the 56-year-old Mass, who graduated from the UW in 1978 and returned as a professor in 1981.

Like Sagan, Mass' public pronouncements are backed by deep scientific expertise. Those computer models forecasters use? He created some of them. That famous convergence zone you hear so much about? It was Mass' early research that helped reveal the way wind flows split around the Olympic Mountains and converge to create a band of clouds and precipitation over central Puget Sound.

Those studies taught him an important lesson about Northwest weather: It's all about mountains and the Pacific Ocean.

The near-constant ocean temperature largely accounts for the region's temperate climate. The double barrier posed by the Rocky and Cascade Mountains shields Western Washington from frigid winds blowing off the interior of Canada. "It's very, very hard to get cold air in here," Mass says.

The westerly flow of air off the ocean largely dictates the region's mix of lush forests, rain shadows, and dry scrub as it rises and falls over mountains — losing moisture en route.

That's a lot of gray days

Local topography can sculpt dramatic events, like the 1979 storm that ripped a 3,200-foot section out of the Hood Canal Bridge. Strong winds blowing over the Olympic Mountains produced a small pocket of low pressure northeast of the mountains. The vortex caused winds to accelerate to 100 mph near the bridge.

"What happened there was an utter surprise," Mass says. Back then, an accurate storm forecast was rare. Mass says he still gets asked what kind of dice he rolls to make predictions. But forecasts have improved greatly. "Over the past 20 to 30 years, we've gone from basically not understanding the local weather here to really having a comprehensive view," he says. "We understand the key local weather features, and we have all these marvelous tools that we didn't have before — high-resolution computer models and satellite and radar imagery."

Mass bikes to work almost every day, and never gets wet. He checks the radar before leaving home, and times his trip to avoid squalls. He's also a master at reading weather data to find the best place to hike and stay dry. "If you know what you're looking for, you can do something outside almost every day of the year here."

Misconceptions still abound about the local weather, including the myth that Seattle is one of the world's wettest cities. Houston, New York, Miami and Boston all get more rain annually than the Emerald City's average of 38.4 inches. But you're not wrong, Mass says, to perceive the region as uncommonly glum. With 228 cloudy days a year, Seattle easily exceeds all those cities on the gray index.

Sandi Doughton: 206-464-2491 or sdoughton@seattletimes.com