The glaciers on Mount Shasta in California are growing because of global warming, experts say.
"When people look at glaciers around the world, the majority of them are shrinking," said Slawek Tulaczyk, a University of California, Santa Cruz, professor who studied the glaciers.
But the seven glaciers on Shasta, part of the Cascade mountains in northern California, "seem to be benefiting from the warming ocean," he said.
As the ocean warms, more moisture evaporates. As moisture moves inland, it falls as snow — enough on Shasta to more than offset a 1 C temperature rise in the past century.
The three smallest of the Shasta glaciers are more than twice the length they were in 1950.
Other glaciers in Norway, Sweden, New Zealand and Pakistan were in the same position as Shasta, but are now shrinking because rising temperatures have more than offset the increased snowfall.
As many as 90 per cent of Earth's mountain glaciers are getting smaller, said Lonnie Thompson from Ohio State University.
A U.S. government inventory found that, with one exception, Shasta's glaciers are the only ones growing on the U.S. mainland, said Andrew Fountain, a professor at Portland State University, who worked on the assessment.
The exception is a small glacier that is shaded in the crater of Mount St. Helens, Wash. It's unlikely to continue to grow once it leaves the shade, scientists said.
Four glaciers on the shady north and east sides of Mount Rainier, Wash., are stable.