Rich Pedroncelli / AP Glaciers on Mount Shasta, seen in the background from the Living Memorial Sculpture Garden near Weed, are still growing, but some scientists say that can't continue.

MOUNT SHASTA — Reaching more than 14,000 feet above sea level, Mount Shasta dominates the landscape of high plains and conifer forests in far Northern California.

While it's not California's tallest mountain, the tongues of ice creeping down Shasta's volcanic flanks give the solitary mountain another distinction. Its seven glaciers, referred to by American Indians as the footsteps made by the creator when he descended to Earth, are the only historical glaciers in the continental U.S. known to be growing.

With global warming causing the retreat of glaciers in the Sierra Nevada, the Rocky Mountains and elsewhere in the Cascades, Mount Shasta is benefiting from 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 UC Santa Cruz. "These glaciers seem to be benefiting from the warming ocean."

Other U.S. glaciers shrinking

Warmer temperatures have 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 in 25 to 30 years. The timeline for the snows at Africa's Mount Kilimanjaro is even shorter, and ice fields of Patagonia in Argentina and Chile also are retreating.

It's a different story at Mount Shasta, at the southern end of the Cascade Range. Scientists say a warming Pacific Ocean means more moist air sweeping over far Northern California. Because of Shasta's location and 14,162-foot elevation, the precipitation is falling as snow, adding to the mass of the glaciers.

"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., who is studying glaciers in Alaska and the northern Cascades of Washington.

Historical weather records show Mount Shasta has received 17 percent more precipitation in the past 110 years. The glaciers soaked up the snowfall and have been adding more snow than is lost through summer melting.

The additional snowfall has been enough to overcome a 1.8 degree Fahrenheit rise in temperature in the past century, according to a 2003 analysis by Tulaczyk, who led a team studying Shasta's glaciers.

By comparison, the glaciers in the Sierra Nevada, which are about 560 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 in the past 100 years, with those exposed to direct sunlight shrinking fastest, said Andrew Fountain, a geology professor at Portland State University who has inventoried the glaciers in the continental U.S. as part of a federal initiative.

He said Shasta's seven glaciers are the only ones scientists have identified as getting larger, with the exception of a small glacier in the shaded crater of Washington state's Mount St. Helens. It formed after the 1980 eruption blasted away slightly more than half the mountain's ice, and scientists believe it won't grow in area once it stretches outside the shade of the crater.

Glaciologists say most glaciers in Alaska and Canada are retreating, but there are too many to study them all.

Four glaciers at Mount Rainier in Washington state are staying about the same size. Those glaciers — shielded from the sun on the north and east sides of the mountain — have received just enough snow to keep them from shrinking, Fountain said.

Growth began in last century

But Shasta's glaciers have been advancing since the end of a drought in the early 20th century. The mountain's smallest glaciers — named Konwakiton, Watkins and Mud Creek — have more than doubled in length since 1950.

Shasta's largest glacier, the Hotlum, grew more than 600 yards from 1944 to 2003 and covers nearly 2 square miles of the mountain's northeastern face. The Whitney glacier grows up to 4 inches a day in winter and is about 2.4 miles long.

Hikers seeking to cross Shasta's glaciers — marked with crevasses as deep as 100 feet — say they are much larger than the boundaries drawn on geological maps.

"I noticed I was traveling down farther than the maps were showing it," said Eric White, the lead climbing ranger at the U.S. Forest Service who has climbed the mountain for 23 years.

Until recently, the same phenomenon that is benefiting Shasta's glaciers was feeding glacier growth in southern Norway and Sweden, the New Zealand Alps and northern Pakistan, according to the U.N. Intergovernmental Panel on Climate Change.

"Best that we keep our eye on the big picture," Thompson said in an e-mailed response about Shasta's unique position.

"The picture points unfortunately (to) massive loss of ice on land, which has huge implications for future sea level rise."

Although Mount Shasta's glaciers are growing, researchers say the 4.7 billion cubic feet of ice on its flanks could be gone by 2100. For the glaciers to remain their current size, Shasta would have to receive 20 percent more snowfall for every 1.8-degree Fahrenheit increase in temperature, said Tulaczyk, of UC Santa Cruz.

Global forecasts show temperatures warming from 2 degrees to 11.5 degrees Fahrenheit by the end of the century if no major efforts are undertaken to reduce the emissions of greenhouse gases.