Harry Hope wrote:
> From The Los Angeles Times, 1/31/10:
>
http://www.latimes.com/news/nation-and-world/la-na-rainer-debris31-20... > Mt. Rainier's melting glaciers create hazard
> Exposed gravel and sediment are increasingly rolling downhill into
> rivers, increasing the threat of flooding in the national park complex
> and Puget Sound communities.
> Reporting from Seattle -
> The fallout from Mt. Rainier's shrinking glaciers is beginning to roll
> downhill, and nowhere is the impact more striking than on the
> volcano's west side.
> "This is it in spades," U.S. Park Service geologist Paul Kennard said
> recently, scrambling up a 10-foot-high mass of dirt and boulders
> bulldozed back just enough to clear the road.
> As receding glaciers expose crumbly slopes, vast amounts of gravel and
> sediment are being sluiced into the rivers that flow from the region's
> tallest peak.
> Much of the material sweeps down in rain-driven slurries.
> "The rivers are filling up with stuff," Kennard said from his vantage
> point atop the pile.
> He pointed out ancient stands of fir and cedar now standing in water.
> Inside Mt. Rainier National Park, gravel-choked rivers threaten to
> spill across roads, overtake bridges and flood the historic park
> complex at Longmire.
> Downstream, communities in King and Pierce counties cast a wary eye at
> the volcano.
> As glaciers continue to pull back, the result could be increased flood
> danger across the Puget Sound lowlands for decades.
> "There is significant evidence that things are changing dramatically
> at Mt. Rainier," environmental consultant Tim Abbe said.
> "We need to start planning for it now."
> Similar dynamics are playing out at all of the region's major
> glaciated peaks, according to research hydrologist Gordon Grant of the
> U.S. Forest Service.
> Climate experts blame global warming, triggered by emissions from
> industries and cars, for much of the ongoing retreat of glaciers
> worldwide.
> North Cascades National Park has lost half of its ice area in the last
> century. Mt. Rainier's glaciers have shrunk by more than a quarter.
> "Every year it's been either bad or really bad," Kennard said.
> "This year it was really, really bad."
> Glaciers buttress immense moraines and stabilize steep slopes.
> As they pull back, the vulnerable terrain is exposed to weather and
> tugged by gravity.
> All recent debris flows on Mt. Rainier have occurred in recently
> deglaciated areas, Grant said.
> "The whole mountain is covered with unstable debris, it's steep -- and
> then you put a lot of water on it," he said.
> Most debris flows are triggered by heavy rain.
> Climate scientists disagree on whether the entire Northwest is being
> hit by significantly stronger storms than in the past, but there's no
> doubt that's the case at Mt. Rainier, Kennard said.
> Precipitation records show more intense rainfall.
> According to stream-flow data, what was once a 100-year flood on the
> Nisqually River now occurs every 14 years.
> In November 2006, a storm dumped 18 inches of rain on the park in 36
> hours, sweeping away a campground and closing the park for more than
> six months.
> Debris flows can carry boulders the size of buses and sweep staggering
> amounts of gravel and sediment into rivers.
> The bed of the Nisqually River below its namesake glacier has risen by
> 38 feet since 1910, largely as a result of debris flows from the
> margins of the rapidly retreating ice, Kennard said.
> The park visitor center at Longmire, with its stone buildings and
> National Park Inn, sits more than 30 feet below the Nisqually River.
> The park constructed concrete-reinforced berms to keep the water at
> bay.
> Every riverbed in the park is rising, Kennard said, and the rate of
> buildup has increased nearly tenfold over the last decade.
> Glacial retreat may be aggravating the flow of sediment, but the basic
> process is as old as the volcano itself.
> In the past, eruptions have unleashed mud flows that smothered
> surrounding valleys and reached all the way to Puget Sound.
> From the 1930s through the 1980s, Pierce County dredged gravel from
> the Puyallup River system almost every year to reduce the risk of
> floods, said Lorin Reinelt, program manager for the county's
> flood-management plan.
> Most dredging ended by the early 1990s, as concern for fish habitat
> took precedence.
> Officials also realized that digging out gravel provides a brief fix
> at best.
> "In many cases it just fills back up during the next event," Reinelt
> said.
> Communities are trying to figure out what rising levels of gravel and
> sediment from Mt. Rainier will mean for future flood risks -- and what
> they can do about it.
> Short of relocating Longmire, dredging is the only obvious way to keep
> the river from swallowing the park complex, Kennard said.
> Downstream, Reinelt said, a more effective approach might be to move
> levees back to give the rivers more room to spill their banks, meander
> and deposit gravel without affecting homes or businesses.
> "This is a pretty significant issue," he said.
> "It seems like we're on a trajectory that's not likely to reverse any
> time soon."
BEFORE ON THIS PLANET.
EMERGENCY! WE ARE NOT ACCUSTOMED TO ANY CHANGE AT ALL. ANYTHING AND
EVERYTHING IS BEING DIRECTLY CAUSED BY AGW.
