Mesa Verde National Park officials have decided to close the Spruce Tree House indefinitely because of rock fall concerns discovered during an inspection in November.

Officials said they plan a full geotechnical assessment.

Spruce Tree House is the park’s third-largest cliff dwelling and one the best preserved site in the Southwest. It’s also the park’s most visited cliff dwelling.

A rock fall prompted park officials to close the southern portion of the site in August. After an evaluation in September, the entire site was closed to the public in October.

In November, a climbing team composed of National Park Service employees from Chiricahua National Monument, Rocky Mountain National Park and Arches/Canyonlands National Parks completed a scaling project at Spruce Tree House. Loose rock was removed, but other problems were found, park officials said.

Spruce Tree House may still be viewed seen from an overlook near the Chapin Mesa Museum. Rangers plan to provide guided talks through March 5 and then be available at the overlook for visitors’ questions, the park said. The Petroglyph and Spruce Canyon hiking trails will be accessible from a point south of Spruce Tree House.

A sandstone arch is present in the Spruce Tree House alcove, just above the cliff dwelling. Stabilization work was performed in the 1940s and ’60s, but erosion may require additional engineering work to stabilize the arch.

Officials plan a four-phase stabilization plan. The first includes a light detection and ranging inspection to obtain a structure profile and to collect geotechnical information. In the second phase, engineers plan to conduct three-dimensional computer-based analyses of the original condition, 1960s stabilization and probable 2016 stabilization, using information from Phase 1 as a chronological modeling sequence. Park officials said Phase 3 includes developing plans, specifications and gathering information to complete stabilization work. Phase 4 will be the performance of that work.