USGS detects small earthquake-like signal before rock slide in Rocky Mountain National Park

A rock slide has closed a portion of Rocky Mountain National Park. The slide happened in the Upper Chaos Canyon area of the park on Tuesday. 

The photo from Google Earth shows several outcrops on the south shoulder of Hallett Peak that came down about 4:30 p.m. Tuesday. Rainstorms are predicted in the forecast for the area through July 3 which may contribute to additional rock fall activity. No one was injured. 

The U.S. Geological Survey says the slide was "preceded ~100 seconds earlier by a M1.5 earthquake-like signal located at or near the surface in the area where the landslide occurred."

Scientists say alternatively "sudden rockfalls with significant free-fall can generate signals that look like shallow earthquakes."

RMNP closed all areas of Chaos Canyon to the west of Lake Haiyaha to all users due to the rock fall activity and potential impacts. the closure will remain in effect until the projected rainstorms pass and the slope can be evaluated by National Park Service geologists. 

Additional Information from RMNP:

The hiking trail to Lake Haiyaha, Lake Haiyaha itself, and hiking trails on the north side of Hallett Peak remain open. The bouldering area in lower Chaos Canyon, on the north and east shore of Lake Haiyaha, will remain open.

Park visitors planning to recreate in rocky terrain areas of the park are reminded to always practice due diligence and use caution. Rocky slopes on and near mountain peaks can be unstable. Recreation users should know their own limits and choose routes that are within the abilities of everyone in their party.

For additional information on Rocky Mountain National Park, visit www.nps.gov/romo or call the park's Information Office at (970) 586-1206.