Standing atop Yosemite's tallest peak in August 1950, Hal Klieforth looked out across the Lyell glacier and marveled at how solid and unyielding it appeared.

"It was like Grand Canyon or the Sierra itself," the 81-year-old meteorologist said recently. "It had been there for many years and probably would be there for many more."

Today, as the boulder-strewn sheet of ice recedes in the summer sun, Klieforth is no longer so confident. "Now I guess there might be more people making a pilgrimage to these glaciers before they go," he said.

No longer is climate change a distant drama of shrinking polar ice caps. As year-round ice fades from the saw-toothed summits of the Sierra Nevada, as Klieforth and others watch a world change in their lifetimes, it's clear an unwelcome reality is at our doorstep: Global warming is local warming.

Just as rising worldwide temperatures are sowing problems in the far north and parts of Antarctica, so, too, are they bringing big changes to our own northern exposure in the Sierra and other mountain regions.

You can see it in the dead rust-red pines west of Yosemite National Park, the fading easel of wildflowers near Carson Pass south of Lake Tahoe and the parched bare banks of lakes and reservoirs. You can smell it in the acrid ash-gray smoke from a siege of early-season wildfires that has choked much of the region for weeks on end.

You can hear it in the quiet murmur of small streams that once rushed noisily downhill in July; in the whoosh of cars over Tioga Pass after Thanksgiving – a time when the white-knuckle road crossing, the highest in California, was always closed by snow prior to 1975; and in the voices and observations of scientists, resource managers and mountain residents.

Behind the counter at Sorensen's Resort, along Highway 88 in Alpine County, John Brissenden greets visitors with a walrus mustache and a Santa Claus smile. Ask about global warming, though, and his tone turns less jovial.

"My fan budget has gone through the roof," said Brissenden, co-owner of the rustic facility which advertises on a postcard that its air-conditioning is "aspen-powered."

"We just can't count on the aspens anymore," Brissenden said. "We have to have a fan in every cabin."

Ten years ago, S.P. Parker routinely guided climbers up an ice-filled chute in the high Sierra called the Mendel couloir. Now that icy staircase has turned to rock and dirt.

"Everything's melting more," said Parker, co-owner of the Sierra Mountain Center in Bishop. "It's kind of depressing to watch it happen."

Even underground, ice is not safe.

In his office near the Oregon border, David Larson keeps a picture of Merrill ice cave – located on the Modoc plateau north of the Sierra. The photo, taken in 1990, shows a giant punch bowl of ice in the cave's lower chamber, several feet thick, hard as a hockey rink. In the early 20th century, people ice-skated on it.

One afternoon this spring, Larson walked down a steep series of steps into the cave and directed the amber beam of his head lamp toward the cave floor. The ice had vanished, leaving behind a jagged jumble of rock.

"It's kind of shocking," said Larson, chief of resources at Lava Beds National Monument. "Ice is almost like a species that is going extinct."

Sierra's plight reflected across West

What's happening here is one ember in a larger fire. Higher elevation landscapes across western North America and the world are warming faster than the rest of the globe – and suffering the consequences.

In British Columbia, mountain pine beetles have devastated a swath of forest one-third the size of California, in part because winters are no longer cold enough to keep the pests in check. In Montana, Glacier National Park is expected to be glacier-free in 25 years.

"It's the far north and the higher elevations that are seeing the impacts first," said Joan Clayburgh, director of the Sierra Nevada Alliance in South Lake Tahoe. "And when it comes to California, it doesn't get any higher than the Sierra."

First in an occasional series: In coming months, writer Tom Knudson and photographer Randy Pench will continue to travel the Sierra, tracking the footprints of climate change. To add your knowledge, memories or historical photos, go to Knudson's blog, "Sierra Summit," at www.sacbee.com/sierrawarming. There, he will post his observations, link to research and first-person accounts, and converse with readers. Call The Bee's Tom Knudson, (530) 582-5336.