Hikers exploring Rocky Mountains National Park narrowly escaped a huge rockslide, and captured the whole event on video. Several visitors to the park were partway up Hallett Peak, a mountain known for its outstanding views and popular with hikers and climbers, when they heard a rumbling sound as a huge chunk of the south face collapsed.
Rock from the area slid into Upper Chaos Canyon above Lake Aihaya, but no visitors were injured. The National Park Service advised hikers to avoid the area, as it may still be unstable.
The video, which you can watch below, was captured by Ryan Albert and shared on Instagram by the Bouldering Guides to Mount St Helens and RMNP.
“Visitors planning to recreate in Upper Chaos Canyon or on the south slopes of Hallett Peak are advised to avoid traveling in the area,” said NPS officials. “It will take some time for the slope to stabilize and there is a significant possibility that additional rockfall may occur at any time.”
What causes rockslides?
Rockslides happen when the structure of a mountain is no longer strong enough to resist the gravitational force upon it. They can be caused by earthquakes, high precipitation, natural erosion over time, or temperature variations. They can also occur when mining operations are taking place.
During a rockslide, the surface of the rock ruptures, separates from the base and slides along it, which can cause further damage and lead to more rock detaching. Movements can range from a single block of rock to whole mountainsides, and other rocks are broken and loosened as the mass moves downhill, causing sudden, tremendous damage.
Safety advice is the same as for landslides and avalanches: keep a close eye on the weather report, and check for any local warnings before heading out. Listen for any unusual sounds (such as cracking or rumbling) and sudden changes to the landscape like abrupt rises in water levels or cracking underfoot.
