A visitor to Yellowstone National Park has been sentenced to seven days in jail for trespassing near an active geothermal geyser.

Washington man Viktor Pyshniuk, 21, walked off the boardwalk near Steamboat Geyser, the National Park Service and Justice Department said in a news release. He was photographed in the off-limits area by a park employee, who reported the incident to Yellowstone National Park law enforcement.

According to the release, he had clearly crossed over the fence and was walking up the hillside within 15-20 feet of Steamboat Geysers steam vent.

Pyshniuk told park law enforcement that he left the boardwalk to take photos, the release said.

Steamboat Geyser is the worlds tallest active geyser.

It has erratic and unpredictable eruptions that can rise anywhere from six to 300 feet high, the park website states . In the last four years, the intervals between eruptions ranged anywhere from three to 89 days.