The Upper Terrace Drive near Mammoth Hot Springs in Yellowstone National Park reopened to vehicles on Monday after rangers had temporarily closed the road due to a new thermal feature.
Maintenance crews installed temporary concrete barriers and eliminated three parking spaces around the thermal feature to help protect the feature from visitor and vehicle impacts, according to a statement released by the park’s public affairs office.
“The activity is changing and the thermal feature is evolving,” said Dr. Hank Heasler, park geologist. Heasler said the concrete barriers “are a temporary measure to allow vehicle access to the Upper Terrace Drive while options are investigated.”
The thermal feature became visibly active in May near the Upper Terrace parking lot and began flowing from a new spot under the edge of the pavement last week.
Geologists drilled two holes a half-meter (20 inches) deep into the pavement to investigate the presence of water under the roadbed. Thermal water is now streaming at approximately one gallon of water per minute from one of the holes.
Staff will continue to monitor the thermal feature and reassess restrictions as needed.