In this photo taken on August 26, 2009 you can see the dust from a rock slide has obscured the view of Half Dome.
Geologists are monitoring the cliffs behind Yosemite's Ahwahnee Hotel after tumbling boulders from the Royal Arches formation forced the evacuation of all 300 guests beginning at about noon Wednesday.
Park spokesman Scott Gediman said a series of falling rocks, some as large as microwave ovens, tumbled at least 100 feet from the base of the cliff and into the valet parking lot, where several cars were damaged. No injuries were reported.
Dust from the avalanche obscured views of Half Dome for a time.
Guests of the historic 125-room hotel were directed to the south lawn behind the hotel while geologists checked the stability and assessed the likelihood that more rocks would fall.
In October park officials permanently closed one-third of Curry Village because of rockfall danger.
Earlier this year, an Associated Press examination of records found that rock falls in and around 600-cabin Curry Village have been happening more frequently in the past several years, with two people killed and about two dozen injured since 1996.
And yet, the park service has repeatedly rebuilt and repaired the lodgings rather than bar the public or post warnings in a lodging complex that federal geologists warned earlier this year is mostly within a potential rock fall zone.
"To me, that's irresponsible," said Deanna Maschmeyer of Monterey, who ran with her two children from their cabin as the equivalent of 570 dump trucks of rock shook the ground Oct. 8. "Now that I've lived through it, I can't believe it's safe. I will not stay there again."
Falling rocks at one of America's most popular parks have led to lawsuits and scientific debate over whether the increasing danger is attributable to construction in the park.
Now, in the wake of the near-catastrophe last month, a park advisory committee could decide as early as this week whether to shut down permanently as much as half of Curry Village, which has been around for more than a century.
Park officials say that over the years, they have carefully weighed the safety of visitors against public demand for lodging amid one of the world's most spectacular natural wonders.
Curry Village is the most family-friendly lodging in the park, consisting of cabins, stores and restaurants run by an outside company. It is in Yosemite Valley, beneath the unstable granite of Glacier Point.
Since 1999, 20 of the structures at Curry Village have been directly hit by boulders and many more have been damaged by flying rocks.
At least 535 rockfalls have hit Yosemite Valley since 1857, killing 14 people and injuring 62--more than at any other national park. Yosemite Valley is easily the most collapse-prone place in a park that receives over 3 million visitors a year.
Although park officials attribute the increased number of falls at Curry Village to nature, two studies have concluded that human activity above Glacier Point contributed to two fatal rock collapses in the late 1990s -- the one that killed the student geologist at Curry Village, and another at the nearby Happy Isles nature center.
In the Happy Isles accident in 1996, the 245 mph air blast from a massive avalanche knocked down and denuded 1,000 trees across 32 acres, killing a 20-year-old visitor, paralyzing another and injuring 12 more people.
Two university scientists later concluded that thousands of gallons of water leaking from a septic system for public restrooms on the overlook had seeped into crevasses and loosened the rock.
The professors also found that many subsequent rockfalls coincided with the release of water from a 147,000-gallon storage tank atop Glacier Point. It was one of those rockfalls that killed Terbush.
More recently, the paving of a parking lot and other construction altered runoff patterns on Glacier Point, contributing to other rockfalls, one of the scientists, Chester F. "Skip" Watts, a geology professor at Radford University in Virginia, said in an interview. "That's what we are seeing now," he said.
One likely spot for the next big rockfall is across the valley on Middle Brother Peak, where a 700,000-ton slab of granite hangs precariously 2,500 feet above an undeveloped area. Unlike Curry Village, it is posted with signs alerting drivers of the danger. They are prohibited from stopping, even momentarily, to admire the view.