The trail is scheduled to open May 11 but not before the narrow trail is cleared of snow, which is 15 feet high in some spots, said Denis Davis, the monument's superintendent.

In recent years, the spring opening has been easy, but the snowpack this year is 130 percent of normal.

"Our long-term employees are saying this is the way winter used to be," Davis said Friday.

Earlier this month, people began shoveling the trail, which climbs 1,160 feet to a cave system in the Wasatch Mountains in Utah County.

About 15 people, including volunteers from Hill Air Force Base, were expected to work this weekend.

There's been progress on the first half of the trail but another portion, with high drifts and avalanche chutes, will be more difficult, said Davis, who was unsure if the trail will be ready by the scheduled opening.

The 250-acre monument, about 40 miles south of Salt Lake City, has about 110,000 visitors per year.