Expanding cracks and fissures at Grand Teton National Park in Wyoming have prompted officials to close certain areas to tourists.

Hidden Falls and Inspiration Point are now closed to tourists due to a possible safety hazard and park rangers are initiating a risk assessment, according to a statement from the National Park Service.

Superintendent David Vela said, “Human safety is our number one priority, and with an abundance of caution we are temporarily closing this area until we can properly assess the situation.”

Although it’s unclear how the cracks appeared, it could be due to seismic activity in the area.

Grand Teton National Park sits atop the Yellowstone supervolcano, which last erupted 630,000 years ago and ejected 240 cubic miles of rock, ash and volcanic dust into the sky and left a 34-mile-by-50-mile depression in the ground.

If there was an eruption of the Yellowstone supervolcano, which government officials and scientists have said is unlikely, the result would be a devastating amount of ash and sulfur spewed into the air. That, in turn, could destroy crops and even alter the climate.

The powerful eruption of Mount Tambura in 1815 lowered global temperatures, triggered extreme weather and led to crop failures.

Officials said they do not know how long the closure will remain in place.