Mt. Rainier's melting glaciers create hazard
Harry Hope
From The Los Angeles Times, 1/31/10:
http://www.latimes.com/news/nation-and-world/la-na-rainer-debris31-2010jan31,0,604880.story
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."
________________________________________________________
Harry
miles
Many on the left seem to feel that melting glaciers can only occur from
higher temperatures. They need to take a look at Kilimanjaro. It's
layer of ice at it's peak has been declining for decades and some feel
will disappear in the not so distant future. However, no scientist has
stated this is from any man made cause let alone higher temperatures.
In fact, the average temperatures at its peak have fallen.
For those that don't know, snow and ice can evaporate even with air
temperatures well below freezing. You won't find the likes of Al Gore
explaining how though.
boo-radley
2000-2009 warmest decade on record
Peter Franks
Glacier melt, slurries, and a changing environment HAS NEVER HAPPENED
BEFORE ON THIS PLANET.
EMERGENCY! WE ARE NOT ACCUSTOMED TO ANY CHANGE AT ALL. ANYTHING AND
EVERYTHING IS BEING DIRECTLY CAUSED BY AGW.
What's next, a report that a 6-year old got a hangnail because of AGW?
Peter Franks
What's the range of that record?
Siobhan Medeiros
> On 1/31/2010 8:16 AM, Harry Hope wrote:
>
> Many on the left seem to feel that melting glaciers can only occur from
> higher temperatures. They need to take a look at Kilimanjaro.
> It's
> layer of ice at it's peak has been declining for decades and some feel
> will disappear in the not so distant future. However, no scientist has
> stated this is from any man made cause let alone higher temperatures.
http://www.time.com/time/health/article/0,8599,1934203,00.html
Wrong again, loser.
I M @ good guy
1421-1430 was 2 degrees warmer.