The seven largest of Mount Hood's 11 glaciers have already shrunk an average of 34 percent since the beginning of the last century, according to calculations by Keith Jackson, a Portland State University graduate student.
PORTLAND, Ore. — Generations know Mount Hood as a landmark for the ages, with an icy crown of gleaming glaciers that supply the streams we drink from, catch fish in and grow food with.
It is Oregonians' playground, retreat and beacon on the horizon. It is Oregon.
But its glaciers now vanish before our eyes, melting away faster as years slide by and our world grows warmer. The mountain is changing at a speed that will, in our lifetimes, alter its look and character -- and its capacity to support so much we depend on.
The seven largest of Mount Hood's 11 glaciers have already shrunk an average of 34 percent since the beginning of the last century, according to calculations by Keith Jackson, a Portland State University graduate student who is part of a glacier research team financed by the National Science Foundation and NASA.
It happens even faster now, as rising temperatures accelerate change in the region. Scientists in the University of Washington's Climate Impacts Group predict the Northwest will warm nearly as much in the next 20 years as it has in the last 100 -- about a degree Fahrenheit.
"In 20 years, it's going to look a lot different, without a doubt," said Andrew Fountain, an associate professor at Portland State heading the research project, which examines and catalogs western glaciers. "The glaciers are continuing to retreat. They're getting a lot smaller. The glaciers today look a lot different than 20 years ago."
Mount Hood's glaciers are especially vulnerable to global warming because they hang onto a lonely volcanic peak at lower elevations and are closer to balmy ocean weather than ice in many other mountain regions. Living in an atmosphere that is already warmer, they are that much nearer the point of no return.
Glaciers in the Northwest and nearby Canada are melting faster than any other mountain glaciers in the world, said Mark Dyurgerov, a glacier scientist at the University of Colorado's Institute of Arctic and Alpine Research.
Each year Mount Hood's glaciers pour out roughly 4 billion gallons of meltwater, enough to fill more than 6,000 Olympic swimming pools. It rushes down the mountain in frigid streams that join Oregon's signature rivers, seasonally jammed with migrating salmon that live or die on cool water. Those rivers drive dam turbines that generate electricity to light our homes before draining, finally, into the Pacific Ocean.
Although melting glaciers erode a resource, they also drive sea levels up. Pacific Northwest glaciers have contributed about 17 percent of the icemelt outside Greenland and Antarctica that is credited with raising ocean levels from 1961 to 2003, Dyurgerov found.
Sandy Glacier, on Mount Hood's west slopes facing Portland and a headwaters of the Sandy River, covers about 60 percent less ground than it did a century ago, according to Jackson.
But the best-studied of Mount Hood's glaciers, Eliot, is tucked into the northeast slope, facing Hood River. Eliot Glacier's erasure over the past century tells a story of slow violence and defeat.
Eliot muscles its way down the mountain's shoulders with the force of a thousand bulldozers, creaking and cracking, shoving aside boulders like peas. Its vast mass of silvery blue ice is very much a living thing.
It depends, as we all do, on the skies and the seasons. It collects snow near the mountain's summit, packing feathery flakes into rock-hard ice. Eliot's ice, and that of its sister glaciers, carved and gouged Mount Hood into the mighty spire that it is.
But Eliot has lost at least half of its ice in the last 100 years, Jackson estimates. That's no surprise to climbers: They no longer scale certain old and established routes to the summit because rocks and ice once locked solidly in place now break loose, falling in dangerous showers. A California climber two years ago plummeted into a crevasse that had opened earlier in the season than his rescuers had seen before.
"Warming and the receding glaciers are very much affecting the recreation potential and the dangerousness of it on all sides of the mountain," said Vera Dafoe, who has long led hikes on the mountain for the Mazamas, Portland's climbing group, and helped monitor Eliot Glacier. "It has changed enormously."
Torrents of water are sometimes unleashed as glaciers melt, blowing out roads and bridges. Dissolving ice flushes silt into rivers, clogging the irrigation systems nearby agriculture depends on.
Eliot no longer covers the ground that maps say it does. Its surface -- a fantastic sheet of cracks and spires that is its own tourist attraction -- sinks like a deflating balloon.
There is little question why.
Temperatures at Eliot Glacier have trended up, in fits and starts, for the past 100 years. In the past 50 years they averaged about a half-degree warmer than the first half of the century, according to Oregon Climate Service calculations.
The past decade in the Northwest was the warmest on record. Average low temperatures at Eliot Glacier have been above freezing during at least six of the last 12 years -- more than any such period in the last 110 years.
Although a winter of heavy snow like the one just past may seem to break the trend, what really matters to the glacier is whether conditions throughout the year let it add more bulk than it loses from melting.
For many years now, the answer has been no.
Those who tramp around Mount Hood know its glaciers have been shrinking for many decades. Glaciers routinely cycle between advancing downhill during cool, snowy periods and shrinking during warmer, drier ones.
But today they are receding faster than researchers have ever seen. There is wide agreement among scientists that human burning of fossil fuels has driven greenhouses gases to their highest levels in at least 600,000 years, warming the Earth especially during the last few decades and speeding the glaciers' demise.
Anticipated consequences for the Northwest include dwindling snowfalls; forests dying of insect outbreaks; and cool, clear streams becoming too warm for salmon to survive, researchers predict.
"There's lots of reason to be concerned about sensitive ecosystems in the Cascades," said Alan Hamlet, a research scientist with UW's climate group who has worked on some of the most thorough studies of regional climate shifts. "We're likely to see some pretty alarming things happening."
Mount Hood is not the only mountain losing its signature ice. From the Alps in Europe to Mount Kilimanjaro in Africa and Glacier National Park in Montana, glaciers are vanishing.
"It's almost universal that all glaciers are retreating," said Peter Clark, a professor at Oregon State University and an international authority on glaciers. "The signs of retreat are dramatic and accelerating."
It signals that "the cause of that change is overwhelming other factors," he said. "The fingerprint of global warming is increasing on a global scale."
Eliot Glacier starts about 1,000 feet beneath Mount Hood's 11,239-foot summit. It is named for Thomas Lamb Eliot, the first minister at Portland's First Unitarian Church. It descends some 4,000 feet down the mountain to about 6,000 feet above sea level on the mountain's northeast slope.
At least, it used to.
Portland businessmen built the Cloud Cap Inn in the late 1800s on a ridge overlooking the glacier, roughly even with its toe. Cloud Cap was one of the West's first high-country hotels, and innkeepers could chip ice from the glacier to keep food cold.
But the glacier has since pulled its toe almost a half-mile away and up the mountain as ice melted, slowly at first and then faster.
Kate McCarthy's father bought the inn in about 1920. She remembers him taking her and her sister exploring the glacier nearby.
"You couldn't do that now, because there's no glacier there," says McCarthy, who lives above Parkdale.
Portland State researchers have built upon measurements the Mazamas began in the 1920s. The analyses show Eliot Glacier has been shrinking almost since it was first described by scientists at the turn of the last century. The main exception was a cooler, snowier period beginning in the late 1940s and 1950s -- and possibly a couple years about 2001 -- that helped it bulk up.
Jackson has picked his way across its craggy surface the last two summers to look even closer. Ice now and then crashes down the upper reaches of the glacier, far above him, in avalanches that are probably more frequent as the glacier withers.
PVC stakes sunk into the ice tell him how fast the glacier is traveling and act as a barometer of its size: The smaller a glacier, the less bulk weighs it down, and the slower it moves. It cannot replenish ice melting at its lower edge, which then melts faster.
In the 1940s, the glacier flowed about 14.1 feet per year. In the 1960s and 1980s, it sped up to about 22.6 feet per year as the slug of snow it added during the cooler middle of the century coasted downhill.
But since 2004 it has slowed to just 7.5 feet per year -- its most sluggish on record and a sign of its swift shrinkage.
The glacier gets help from crumbly volcanic rock that falls into the ice and collects on top of the glacier's lower reaches as the ice melts. Robert Schlichting, a science teacher at Cleveland High School, built monitors to track the melting. He found that thin layers of the rock absorb sunlight, melting the ice faster. But once about an inch collects, it insulates the glacier.
Warmer temperatures now outdo that insulation, though. They bring spring earlier and push winter later, so although more moisture may fall, it is likelier to be rain than snow. Rising temperatures also melt the ice faster over more of the year.
"You have to ask: How long will glaciers persist on Mount Hood?" said Karl Lillquist, a professor at Central Washington University. He studied the peak's glaciers as a graduate student in the late 1980s and was surprised how much they had melted when he re-examined them in the last several years.
Historic photographs show the edges of Eliot Glacier nearly even with ridges -- called moraines -- on both sides. Now the moraines are dark cliffs looming above the sunken ice.
The glacier has lost roughly as much ice at its base in the last 15 years as in the previous 50 years. If it contracts at the same slow rate it did over most of the last 100 years, it would survive for almost 600 years, Jackson estimates.
But if it -- and the other glaciers on the peak -- shrinks at the pace of the last 15 years, it will disappear in just 180 years -- leaving Oregonians a view of slick, gray rock.
As it retreats to higher, cooler and shadier elevations, the glacier may preserve more of its ice. But if temperatures continue to rise, warming will chase it uphill, PSU's Fountain says.
"Glaciers find some protection that way, but the climate keeps going until" -- he snaps his fingers -- "they disappear."
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Source: Knight Ridder/Tribune Business News
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