The Colorado Department of Transportation has shut down Loveland Pass after a rock slide on Tuesday afternoon.
The slide on U.S. 6 between Arapahoe Basin and Keystone ski areas was 50 feet wide and about 7 feet deep, said CDOT spokeswoman Crystal Morgan.
The pass remained closed at 10 p.m. and there was no estimated time for reopening.
"There were no vehicles involved," Morgan said shortly after the closure at about 4:15 p.m..
Crews were on the scene Tuesday. Once they secured the area they would determine whether the pass could reopen after the rocks and debris were removed from the road, Morgan said, or if more work could be needed to stabilize the area above.
"We want to be sure the area above it is secure before we reopen," Morgan said.