Park officials said Thursday they're evaluating how to address the problem.
Meanwhile, they're telling visitors not to hike into the affected area. They say the danger of stepping through a solid-looking crust of soil into boiling-hot water is just too high.
The hot spot has closed Firehole Lake Drive, a 3.3-mile loop six miles north of Old Faithful that takes visitors past Great Fountain Geyser, White Dome Geyser and Firehole Lake.
Naturally changing thermal features often damage Yellowstone's roads and boardwalks. Park spokesman Al Nash says fixing this damage will be a bit more challenging than the typical repair.