The Upper Terrace Drive near Mammoth Hot Springs in Yellowstone National Park reopened to vehicles on Monday after rangers temporarily closed the road due to a new thermal feature that was impacting the drive.

Maintenance crews installed temporary concrete Jersey Barriers and eliminated three parking spaces around the thermal feature to help protect the feature from visitor and vehicle impacts.

“The activity is changing and the thermal feature is evolving,” said Dr. Hank Heasler, park geologist. “The Jersey Barriers are a temporary measure to allow vehicle access to the Upper Terrace Drive while options are investigated.”

The thermal feature became visibly active this 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.