YOSEMITE NATIONAL PARK — Geologists are monitoring the cliffs behind Yosemite's majestic Ahwahnee Hotel after tumbling boulders from the Royal Arches formation forced the evacuation of all 300 guests beginning at about noon Wednesday.
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, park spokesman Scott Gediman said. No injuries were reported.
"It's all very mellow right now," said park spokesman Scott Gediman. "We asked people to leave as a precaution while geologists investigate."
Dust from the avalanche temporarily obscured views of Half Dome.
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. Gediman expected they would be allowed to return to their rooms by late afternoon. Slideshow: America's national parks
Rockfall is a potential danger in the park formed when retreating glaciers cut dramatic formations from solid granite. Royal Arches towers 1,600-feet behind the Ahwahnee, a massive arts-and-crafts-style hotel with dramatic views of Half Dome, Yosemite Falls and Glacier Point.
In October park officials permanently closed one-third of Curry Village under Glacier Point after the equivalent of 570 dump trucks of rock hit 17 cabins and forced the evacuation of more than 150 youngsters on a field trip. No one was seriously injured.
The century-old Curry Village is the most family friendly lodging in the park, consisting of cabins, stores and restaurants run by an outside company.
An Associated Press story last year said that geologists have warned for at least a decade that the granite face of Glacier Point above the village was dangerous. Despite two deaths and an increase in the frequency and severity of the rockfalls since 1996, park officials had been reluctant to act.
Gediman acknowledged Wednesday that rockfall is a potential danger and something park geologists monitor.
"Yosemite continues to be affected by rockfall and rockfall continues to be a part of the ongoing development of Yosemite Valley," he said.
Copyright 2009 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.