Illuminating Spruce Tree House at Mesa Verde National Park has been a highlight of the park's annual open house, but the possibility of rockfall has led to cancellation of this year's event/NPS

Worries that the rock ceiling in Spruce Tree House might peel off have prompted Mesa Verde National Park officials to cancel their annual open house and luminaria event scheduled for December 8.

With the ongoing concern over the stability of the rock arch in the Spruce Tree House alcove, park officials have determined that entering the alcove to place lanterns in the site is an unnecessary risk to staff members.

“I regret that we have to cancel the event,” Mesa Verde Superintendent Cliff Spencer said Friday in a release. “But I cannot justify allowing our staff into Spruce Tree House to place and light the lanterns with the risk of rockfall present.  We’re looking forward to the geotechnical analysis of the alcove arch next year. That will hopefully give us a better insight into the current condition, and future steps.” 

A natural sandstone arch is present in the Spruce Tree House alcove, just above the cliff dwelling.  Early stabilization work was performed in the 1940s, with additional stabilization work completed in the 1960s.  Natural erosion processes, including the settling of the arch, have been affected by the early stabilization work, so that modern engineering techniques may be necessary to ensure continued stability of the arch.

It was August 2015 when a rockfall at Spruce Tree House led to closure of the southern portion of the site for visitor safety. All of Spruce Tree House has been closed to visitors since October 2015.