Woman suffers burns while walking off-trail in thermal area by Yellowstone's Old Faithful

A 60-year-old woman was walking off-trail in Yellowstone National Park when she suffered burns from scalding water in a thermal area by Old Faithful, park officials said.

The woman was walking with her husband and their dog in a thermal area near Mallard Lake Trailhead on Monday afternoon "when she broke through a thin crust" over the extremely hot water, suffering second-degree and third-degree burns to her leg, the National Park Service said.

The woman, who was visiting Yellowstone from New Hampshire, was taken to a park medical clinic and later flown to a hospital for further treatment, officials said.

Her husband and dog were not hurt, park officials said.

"Visitors are reminded to stay on boardwalks and trails in hydrothermal areas and exercise extreme caution," Yellowstone National Park said in a statement. "The ground in these areas is fragile and thin, and there is scalding water just below the surface."

Park spokesperson Linda Veress urges visitors to "follow the beaten path.”

“In thermal areas, boardwalks take you to amazing places, protect the park, and keep you safe," Veress told ABC News. "People have been severely burned and killed after leaving the boardwalk or reaching into hot water."

Pets aren't allowed on boardwalks or hiking trails, or in thermal areas, park officials noted.

The incident is under investigation, park officials said.