"It covered them with snow and ice, and it blew them off their seat," Mullally said.
"They were lucky."
People needed to be wary of avalanches around this time of year as the warmer temperatures, combined with some rain, had increased the risk of avalanche, Mullally said.
"It doesn't take much," he said.
"There is a lot of snow at 5500 feet, 6000 feet."
None of the three men were injured - seemingly escaping the incident unscathed.
"I think they need to go home and change their undies," Mullally joked, adding the group were happy to see him.
"There were still avalanches going off, and at night of course, you don't know where they are going off."
But they could still hear the boom, he said.