WINTHROP, Wash. - Warm temperatures and drought conditions in the West have changed the migratory patterns of birds and wildlife, but are also impacting another group: skiers, especially cross country skiers.

Some Alpine resorts - which offer downhill skiing - are responding to tough conditions by making snow. But for Nordic centers - known for miles of trails groomed with special tracks for diagonal striding or perfectly flat tracks for skate skiing - snow-making isn't an option.

Faced with a lack of snow, some cross country centers have closed until more snow arrives, prompting skiers to hit the road.

The Nordic skier migration has proved beneficial to Sun Valley, Idaho, and Methow Valley, Wash., just east of the Cascade Mountains in central Washington.

"We are very disappointed to not have skiing at home yet again," said June Lane, a Truckee, Calif., resident who lives across the street from Tahoe Donner Cross Country Ski Center but recently bought a town house near Sun Valley. "We bought passes at TD and I have not skied there once. We have been here since the day before Thanksgiving and the skiing has been fantastic."

The Tahoe Donner center opened Dec. 20 but closed Jan. 19 until more snow arrives. Tahoe Cross Country Center in Tahoe City, Calif., posted on its website: "Trails are currently closed due to insufficient snow coverage." Ski centers in Alaska and other parts of the West also are struggling. Eaglecrest Ski Resort in Juneau, Alaska, closed on Jan. 19.

But the cross country trail system in the Methow Valley is on track to have a record in terms of ski season length. James DeSalvo, executive director of Methow Trails, said they started grooming - setting ski tracks - the week before Thanksgiving, and he expects skiing to continue in April.

Meanwhile, at the Central Sierra Snow Laboratory, a research station run by the University of California, Berkeley, technicians are tracking the drought.

Randall Osterhuber, a snow scientist at the lab in Soda Springs, Calif., said December was a wet month for the northern Sierra near Lake Tahoe - home to about a dozen Alpine and cross country ski resorts. But the snow levels were high, leaving terrain below 7,000 feet without snow, only rain.

According to the U.S. Drought Monitor website, "short-term deficits continued growing in the Sierra Nevada and adjacent Nevada, and intensely dry conditions persisted."

For avid cross country skiers, the only choice has been to go elsewhere.

Yolanda Labia, a Truckee resident who also bought property near Sun Valley, said they're staying for now.

"We visit regardless of conditions in Tahoe, but this year is a special treat," she said.

Lane said she knows others from Truckee who bought places in Sun Valley, and many friends are driving up to ski.

"There is a new term for here now, 'The Galena Triangle,' as the Galena/Wood River Valley always seems to have snow, even in drier years," she said. "Skiing here is a dream come true. It is rather ironic that we now have to drive to (go) skiing."