OLYMPIA, Wash. - The worst is whiteout conditions. It's treacherous and easy to get lost. Climbers can't see, and they have no sense of direction, no sense of movement.
"It doesn't even have to be blowing," said Mike Gauthier, lead climbing ranger at Mount Rainier National Park.
Some climb Mount Rainier in the winter just for the added outdoor survival challenges; others do it as training for bigger mountains. And for a few, the motivation is to be the first person to stand on the summit in a particular year.
In this high-altitude world of blinding snow and frigid wind where one misstep can mean disaster, the rewards are sublime.
"When it's good in the winter, it's Rainier at its best," Gauthier said. He estimates that 250 climbers - and perhaps as many as 500 - attempt the 14,411-foot summit each winter, between late December and March.
Those climbers face deep, soft snow; fierce wind; whiteouts; avalanche hazards; the dangers of hypothermia and frostbite; and the sheer physical exertion of trudging through deep snow.
But once on top, they own the world.
"You are alone. You feel like the whole world is yours," climber Alex Van Steen said.
Fresh snow coats the rocks, tracks and dirt. The trees are draped in snow and the rocks edged in rime. The low winter sun plays hide and seek with the clouds or cuts through the fog.
"But when you get above the clouds and the sun comes out, then you really are alone," Van Steen said.
He is a veteran climber and guide with Rainier Mountaineering Inc. in Ashford, the only commercial outfit that guides on the mountain in the winter months.
Climbers preparing for big mountain expeditions such as Mount McKinley in Alaska - at 20,320 feet, it's more than a mile higher than Mount Rainier - practice by climbing Rainier in the winter months, he said.
On Rainier, they don't face extreme cold, but they learn to climb in a winter environment - how to keep from getting wet, how to keep their camp from blowing away when the wind tops 60 mph, how to navigate when socked in by a snowstorm.
They learn to evaluate avalanche hazards, to make snow caves, to keep their bearings so they don't get lost, and to evaluate when it's best to sit tight, Van Steen said.
Not that it doesn't get cold on Rainier. The temperature drops to 0 or 5 below, and the wind just makes it worse. But the warm, moist air that comes off the Pacific Ocean dumps a lot of snow on the mountain, he said. Snowfall at Paradise often tops 80 feet during the winter.
"The reality is in the winter we're dressed heavily, and the wind chill doesn't affect us much," Van Steen said. In fact, a bigger problem is getting too warm from pushing through deep, soft snow - the lead climber gets sweaty while the rest of the party is chilly.
"That's hard work," he said.
Winter ascents run from December through March and some years into April, which has the best success rate for summit attempts. But climbers can encounter winter conditions as late as June.
The typical ascent heads to Camp Muir, about 10,000 feet above Paradise, and may camp on the way up. From Muir, the party makes its summit attempt over the Ingraham Direct or the Gibraltar Ledge routes.
But sometimes, tired climbers reach Muir only to find it buried in 10 feet of snow. Then they have to dig down to it before they get to rest, Gauthier said.
He too enjoys the pristine appearance of the mountain in winter, with fresh snow covering everything, beneath the bright blue sky - but as a climbing ranger, he has more opportunity to pick his time to go. Regardless of a climber's skills or equipment, when Rainier says, "No," there's no climbing that day.
"But when the weather breaks in the winter, it's special," Gauthier said. "It's like having the mountain to yourself."
Winter means the snow is deeper, the weather colder. The days are shorter, and usually, even nice days aren't nice for very long. "But more than anything it's quiet," he said.