Glaciers on Mount Shasta keep growing

MOUNT SHASTA, Calif. — Global warming is shrinking glaciers all over the world, but the seven tongues of ice creeping down Mount Shasta's flanks are a rare exception: They are the only long-established glaciers in the lower 48 states that are growing.

Reaching more than 14,000 feet above sea level, Mount Shasta is one of the state's tallest peaks, dominating the landscape of high plains and conifer forests in far Northern California. Nearby Indian tribes referred to its glaciers as the footsteps made by the creator when he descended to Earth. Hikers flock to Shasta every summer to scale them.

With glaciers retreating in the Sierra Nevada, the Rocky Mountains and elsewhere in the Cascades, those on Mount Shasta — a volcanic peak at the southern end of the Cascade range — are actually benefiting from changing weather patterns over the Pacific Ocean.

"When people look at glaciers around the world, the majority of them are shrinking," said Slawek Tulaczyk, an assistant professor of earth sciences at the University of California, Santa Cruz, who led a team studying Shasta's glaciers. "These glaciers seem to be benefiting from the warming ocean."

Climate change has cut the number of glaciers at Montana's Glacier National Park from 150 to 26 since 1850, and some scientists project there will be none left within a generation. Lonnie Thompson, a glacier expert at Ohio State University, has projected the storied snows at Africa's Mount Kilimanjaro might disappear by 2015.

But for Shasta, about 270 miles north of San Francisco, scientists say a warming Pacific Ocean means more moist air. On the mountain, precipitation falls as snow, adding to the glaciers enough to overcome a 1.8 degree Fahrenheit rise in temperature in the last century, scientists say.

"It's a bit of an anomaly that they are growing, but it's not to be unexpected," said Ed Josberger, a glaciologist at the U.S. Geological Survey in Tacoma, Wash.

By comparison, the glaciers in the Sierra Nevada, more than 500 miles south of Mount Shasta, are exposed to warmer summer temperatures and are retreating.

The Sierra's 498 ice formations — glaciers and ice fields — have shrunk by about half their size over the past 100 years, said Andrew Fountain, a geology professor at Portland State University. He inventoried glaciers in the contiguous U.S. as part of a federal initiative.