MISSOULA, Mont. -

City prosecutors have decided not to charge the snowboarder who triggered an avalanche in Missoula in February.

That slide from Mount Jumbo buried three people and killed one. It destroyed homes in a Rattlesnake neighborhood just off the 900-block of Holly Street.

Police have been investigating the avalanche since it happened, and this week handed over the report to the city and county attorneys’ offices.

“It’s probably over 30 pages, 16 pages of text,” said Missoula City Attorney Jim Nugent. “Our staff has decided that we shouldn't prosecute.”

According to Nugent and the police report, investigators didn't think charges should be filed either. Nugent said the report shows police did extensive research in the case, talking to the Parks Department, the Missoula Avalanche Center and the people who were on the mountain.

Nugent said there were four of them, ages 13 to 26; three were sledding, the other was the snowboarder.

“Only the snowboarder was in the area where the avalanche occurred,” Nugent said.

Nugent said his office had to decide if the people knowingly trespassed and violated a city ordinance.

“The signage was probably covered because the blowing snow probably stuck to it and covered it,” Nugent said. “But more importantly the police indicated that the people who had entered the mountain hiking up the side of the mountain, were not aware of the seasonal closure.”

After reviewing all of the information, Nugent made his decision. But he says this case was different.

“This is exceedingly unique circumstances and of course we hope it never happens again,” Nugent said. “But in the future I think people can expect that there's going to be signage closing it for avalanche danger as a result of what we've learned this particular winter season.”

Missoula County Attorney Fred Van Valkenburg said Friday his office still needs more time to review the case.