JACKSON, Wyo. — A slow-motion disaster continued unfolding in the Wyoming resort town of Jackson on Saturday, as a creeping landslide that split a hillside home threatened to swallow up more houses and businesses.
The ground beneath the 100-foot hillside had been slowly giving way for almost two weeks before the downward movement accelerated in recent days.
With rocks and dirt tumbling down, officials suspended efforts to shore up the slope and said they were uncertain what else could be done.
“When is it going to go? How long is it going to last? These are the questions we just can’t answer and they’re what everyone wants to know,” town spokeswoman Charlotte Reynolds said.
Authorities said there could be a variety of causes for the slide, including prior construction at the site, warmer weather and a wet winter that put more water into the ground where it acts as a lubricant for unstable rocks and soil.
Experts say the hillside is unlikely to suddenly collapse like the March 22 landslide in Oso, Wash., that killed 39 people. More likely, large blocks of earth would tumble down piece by piece.
But the threat is real and authorities are enforcing an evacuation order in hopes of avoiding injuries. Town officials first noticed significant hill movement April 4. They evacuated 42 homes and apartment units April 9.
By Saturday morning, the shifting earth had bulged a road and a parking lot at the foot of the hill by as much as 10 feet. The groundswell pushed a small town water pump building 15 feet toward West Broadway, the town’s main drag.
The ground had been moving at a rate of an inch a day but is expected to move increasingly faster as time goes on, said George Machan, a landslide specialist consulting for the town.
Rockslides are common throughout the Rocky Mountains in the spring, as melting snow and warmer weather unleashes the region’s dynamic geology. In the early 1900s, a massive slide caused by heavy rains north of Jackson formed a natural dam across a small river. The dam gave way two years later, unleashing a flood that killed six people.