Jersey barriers have been placed on Upper Terrace Drive in Yellowstone to keep traffic and pedestrians away from a new thermal feature/NPS

Asphalt does not stand in the way of thermal features at Yellowstone National Park. That's evident at Upper Terrace Drive, where the appearance of a thermal feature has led crews to use Jersey barriers to keep traffic and pedestrians from impacting it.

The drive near Mammoth Hot Springs reopened to vehicles on Monday after rangers had temporarily closed the road due to the thermal feature that was impacting the drive. Along with installing the temporary barriers, crews eliminated three parking spaces around the thermal feature to help protect it 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.