JACKSON, Wyo. - No one can say precisely when the mountainside collapsing into this Wyoming resort town will give way. But it appears increasingly likely that when it does, it's going to take a piece of Jackson with it.

Workers and residents have watched helplessly in recent days as the slow-motion landslide spanning hundreds of yards split a house in two and inched ever closer to a cluster of businesses below.

Standing at the edge of the slide zone, its rocky slope rising sharply behind him, Jackson Fire Chief Willy Watsabaugh said the rate of movement slowed Saturday, giving crews a chance to get back in and reassess the damage.

Yet the fate of the businesses, houses, and apartment buildings in the slide zone remained in doubt. Experts brought in to assist the town said it was unknown when the slide will come to a rest.

Efforts taken to stop it - including the erection of large concrete walls at the base of the slope - have proved futile.

The concrete walls had been pushed around by the shifting ground and were leaning away from the slope Saturday, when they were relocated to support a makeshift road being built to give heavy equipment better access to the site.

A sudden acceleration last week prompted authorities to suspend their efforts to shore up the slope as falling rocks created a hazard. The work that resumed over the weekend focused on repairing some of the damage already inflicted, such as a break in a sewer line on Friday, town spokeswoman Charlotte Reynolds said.

What triggered the geologic event remains under investigation. Authorities are looking into whether recent construction at the foot of East Gros Ventre Butte made the slope unstable. But they say there could be additional causes, including earlier construction, warmer weather, and a wet winter that put more water into the ground, where it acts as a lubricant for unstable rocks and soil.