A glacial outburst flood and debris flow Thursday at Mount Rainier National Park damaged a road, required help for some park visitors in the area that was affected, and touched off a search for any hikers who might have been stranded. The incident occurred at Tahoma Creek at about 9:40 a.m. Park officials said the flood originated from the mountain's South Tahoma Glacier as approximately a half-acre of the glacier's terminus broke off and quickly released water stored in the glacier. No injuries were reported, but a damaged road had to be closed and officials said the incident serves as a reminder for the public that mountain conditions can become dangerous unexpectedly. The surge was first reported by a park volunteer who was working near Tahoma Creek on an unrelated research project. The volunteer heard a loud roaring sound, followed by the sounds of water moving boulders and the cracks of breaking trees. As the debris flow from the initial outburst crossed Westside Road, the volunteer went to higher ground, according to a park spokeswoman. Another volunteer at Indian Henry's Hunting Ground also heard the loud roar coming from the direction of the South Tahoma Glacier and hiked to a safe location near the suspension bridge over Tahoma Creek to report on subsequent outburst surges. The debris flows were recorded by seismic monitoring equipment at Emerald Ridge in the park at 9:40, 10:30 and 11:30 a.m. and again at 12:40 in the afternoon. The largest event was at 11:30 and generated a flow that reached the Westside Road at approximately 12 p.m., officials said. Park rangers and geologists quickly contacted visitors in the area and helped them across the area impacted by the debris flow. All of the park visitors in the area were accounted for by Thursday evening, but park officials said they would continue to monitor visitor activity in the area. In addition, a Hughes MD530 helicopter from Northwest Helicopters flew two reconnaissance flights Thursday to look for park visitors hiking in the area, view the condition of the trail for possible washouts, and check the South Tahoma Glacier for possible additional outburst geologic hazards. Damage to Westside Road caused the road to be closed at least through the weekend as park personnel continued monitoring Tahoma Creek and assessing damage to the road and nearby trails. Thursday's incident "demonstrates again that Mount Rainier is a dynamic landscape,GÇ¥ said Randy King, the park's superintendent. "Visitors should be aware of their surroundings when traveling in the park. Remember to remain alert for changes in water levels, unusual sounds or shaking of the ground. If you are near a river or stream, move quickly to higher ground.GÇ¥ He said about seven waves of debris flow occurred Thursday afternoon and evening. As the flood moved, it carried sediment, rocks, and uprooted trees and deposited the debris within the Tahoma Creek valley near Mount Wow within the park. A stream gauge on the Nisqually River at National registered the half-foot river rise on Thursday afternoon. The didn't impact property outside the park, according to park officials. A glacial outburst flood is a large, abrupt release of water from a glacier. Exactly how water moves through glaciers and how the sudden floods occur isn't well-known, but geologists report that associated conditions appear to be stagnant and slow-moving ice on the lower part of the glacier, combined with faster-moving ice on the upper glacier.
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