JACKSON (WNE) — A 21-year-old man who entered off-limits terrain to take pictures of Yellowstone’s most dangerous geyser was sentenced June 4 to seven days in jail for thermal trespass, banned from the national park for two years and fined $1,500.

“Trespassing in closed, thermal areas of Yellowstone National Park is dangerous and harms the natural resource,” acting U.S. Attorney Eric Heimann said in a press release about Viktor Pyshniuk, of Lynwood, Washington. “In cases like this one where we have strong evidence showing a person has willfully disregarded signs and entered a closed, thermal area, federal prosecutors will seek significant penalties, including jail time.”

The release said an off-duty Yellowstone employee reported seeing Pyshniuk walking off the boardwalk in the thermal area at Steamboat Geyser in the Norris Geyser Basin, and a park law enforcement officer was dispatched to the scene.

“The employee had taken a photo of the defendant who had clearly crossed over the fence and was walking up the hillside within 15-20 feet of Steamboat Geyser’s steam vent,” the release said.

Steamboat is “the world’s tallest active geyser, but it is also the most dangerous,” the release said. “It has erratic and unpredictable eruptions that can rise anywhere from six to 300 feet high.” 

Yellowstone’s website says eruptions can be so powerful that “mature lodgepole pines have been broken by the downpour, undermined and then washed away by the geyser’s massive discharge.”

During sentencing, Magistrate Judge Stephanie A. Hambrick noted that the 3-foot fencing around the boardwalk is a clear sign the area is closed. She told Pyshniuk the sentence was designed to deter not only him but everyone else from leaving the boardwalk in the area.