From the AP:

CHEYENNE, Wyo. (AP) — The ever-changing thermal geology of Yellowstone National Park has created a hot spot that melted an asphalt road and closed access to popular geysers and other attractions at the height of tourist season, officials said Thursday.

As they examined possible fixes, park officials warned visitors not to hike into the affected area, where the danger of stepping through solid-looking soil into boiling-hot water was high.

Other than that, enjoy your visit.