State's shrinking glaciers: Going ... going ... gone?

MOUNT RAINIER NATIONAL PARK — Like tiny doctors on the belly of a sleeping giant, three National Park Service workers trudged up the middle of the Nisqually Glacier, stepping over tiny creeks and peering down a dizzying chute where water from the melting glacier wormed into the 300-foot-thick slab of ice.

Nearby, a tall plastic pole arced from the ice into the sky. Park scientist Rebecca Doyle knelt at its base, whipped out a tape measure, and began jotting down numbers.

The pole is 41 feet long. Six months ago, in April, it was totally buried in snow and ice. On this recent sunny October day, so much snow had melted that only a few inches of the pole remained buried.

"Wow, that's a lot," exclaimed Paul Kennard, a park service geomorphologist, as he stood holding the pole.

Like Kennard and Doyle here on Mount Rainier, scientists on mountains all over Washington, the most glacier-covered state in the Lower 48, are trying to determine how glaciers are changing. What they are finding here and elsewhere is worrisome: Many of them, such as the South Cascade Glacier in the remote North Cascades, are shrinking quickly — and some are on the verge of disappearing.

While glaciers have ebbed and flowed through the region for millennia — the land where Seattle now stands was once beneath more than half a mile of ice — scientists say global warming is at least partly to blame this time.

And it would be more than a sentimental loss. It could mean less water powering some of the region's hydroelectric dams, filling some drinking-water reservoirs, irrigating farm fields and ushering spawning salmon upstream.

"When people ask me, 'Will glaciers disappear in my lifetime?' I answer, 'Some of them will disappear; all of them are going to get a lot smaller,' " said Andrew Fountain, a glaciologist at Portland State University who is cataloging changes in U.S. glaciers.

Draining savings account

When Army Lt. August Kautz first described the Nisqually Glacier as part of a trip to the summit in 1857, it completely covered the spot where Highway 706 now carries tourists over the Nisqually River on their way to the Paradise Visitors Center.

Today the glacier's bottom section can't even be seen from there.

Like all glaciers, the Nisqually is essentially a river of slow-moving ice. Instead of snow packs, which come and go every year, a glacier acts like a savings account. It stores water as ice, and lets it out slowly when it melts.

The trouble is that Washington's glaciers have increasingly been overdrawn.

The Nisqually is no exception. Between 1913 and 1994, the Nisqually and an icy tributary, the Wilson Glacier, together shrank by 9 percent, according to a study co-authored by Fountain, the Portland State researcher. Since 1994 it has continued to shrink.

The Nisqually is in no immediate danger of vanishing because it is so high on the mountain. But Stefan Lofgren, a Park Service climbing ranger who has been working on the mountain since 1992, ticks off other glaciers that have vanished, or are about to: the Stevens, the Williwakas, the Lower Paradise, the Van Trump, the glaciers on nearby Unicorn and Pinnacle peaks.

Even the snowfield around Camp Muir, the overnight stopping point for thousands of Mount Rainier climbers on their way to the summit, is shrinking. Lofgren predicts the entire 230-acre snowfield will be gone within half a century.

It's happening all around the state's high mountain ranges. The total volume of the glaciers in North Cascades National Park fell by 8 percent between 1958 and 1998, according to one of Fountain's studies. That would be enough ice to fill Lake Sammamish more than twice. In the same period, only 2 percent of the glaciers in the North Cascades grew in size.

The South Cascade Glacier, a remote ice field near Glacier Peak, has shrunk almost every year since 1959, when the U.S. Geological Survey (USGS) began tracking it closely. In 2003, it was half the size it was in 1923, scientists estimate.

On the north side of Mount Olympus, in the Olympic Mountains, the depth of ice on the Blue Glacier has dropped an average of 65 total feet since 1987, according to estimates by University of Washington researchers.

Natural, human causes

Some of the shrinkage of Washington's glaciers over the past century has nothing to do with human-caused climate change.

Starting in the late 19th century, the Northern Hemisphere emerged from what scientists call the "Little Ice Age," and the warmer weather meant smaller glaciers.

Similarly, regional climate forces can make glaciers shrink or grow. A colder winter can bring more snow, for example.

But lately global forces have been shaping Washington's glaciers, scientists believe.

The pattern of shrinking in the South Cascade Glacier, as well as several glaciers in Alaska, for example, suggests a link to broader climate change, said Ed Josberger, head of the ice and climate project at the USGS office in Tacoma.

A shift in regional weather patterns in the late 1980s should have brought more snow and caused the South Cascade Glacier's shrinkage to slow. But rising summer temperatures overwhelmed the additional snow, and the glacier continues to shrink quickly.

Also, for decades the South Cascade Glacier and another glacier in Alaska were polar opposites. Because of regional weather patterns, when one shrank quickly the other did well. But now they are both rapidly shrinking.

Still, it's hard to say the change in a single glacier is the result of human-caused climate change — warming brought by increases in manmade atmospheric gas such as carbon dioxide, cautioned Philip Mote, the state climatologist. Computer programs that predict how climate change happens around the world aren't yet so specific that they can account for a single mountain range, he said.

But what's happening to the glaciers is consistent with what Mote and most other scientists expect.

"We're now at the point where we can say pretty confidently that the warming in the West is due to human activities, and the fact that virtually every glacier in the West is retreating certainly underscores that," he said.

The end of a resource?

In the short term, fast-melting glaciers provide a bounty for some rivers, as more ice turns to water. But when the glaciers shrink too much, summer stream flows will drop off.

"What we're used to now is not normal, and we're not going to have this for very long," said Alan Hamlet, a University of Washington hydrologist studying the effect of global warming on water supply in the West.

Some rivers, like the Cedar, which provides much of Seattle's water supply, aren't fed by glaciers. But glacier-fed rivers could be more vulnerable.

The Nooksack River, near the Canadian border, is fed partly by the shrinking Deming Glacier on Mount Baker.

Its loss could make it harder for the city of Bellingham to store enough drinking water. The city gets some of its water from the Middle Fork of the Nooksack, which begins at the Deming Glacier, said Clare Fogelsong, city environmental resources manager. The loss of that glacier's water could mean further trouble for chinook salmon recovery on the river.

On the Baker River in the North Cascades, Puget Sound Energy expects to lose up to 6 percent of production at its hydroelectric operation as glaciers shrink. That's not a major loss, but it's still enough to power 3,000 homes.

Perhaps most important to the Northwest is the potential impact to the Columbia River. Shrinking Canadian glaciers could limit summertime flows, hurting salmon or perhaps forcing dams to forgo electricity generation and release more water to help the fish.

Yet, as with many other rivers, scientists don't have a complete picture of how important the glaciers are in the Columbia. Different glaciers melt at different rates, and not all of that has been measured. Then there's the challenge of sorting out how much water in a river came from glaciers versus annual snowpack.

Some answers might come from a new Canadian-led research project to decipher how shrinking glaciers will affect water supplies in western Canada, including the Columbia River.

But for now, many computer predictions of the impact of global warming on water supplies in the West still don't even account for shrinking glaciers, Hamlet said.

"Part of it I think is people have been slow to realize how fast this is going," he said.

Warren Cornwall: 206-464-2311 or wcornwall@seattletimes.com

Information in this article, originally published November 1, 2006, was corrected November 2, 2006. A previous version of this story incorrectly stated that the Blue Glacier in the Olympic Mountains has dropped an average of 65 feet annually since 1987. It has dropped an average of 65 feet total since 1987.