Large avalanche thunders down Tumalo Mountain

(Update: Comments from avalanche expert, snow biker in area)

A large, potentially deadly avalanche about 9 feet deep thundered down the northeast slope of Tumalo Mountain on Wednesday morning, but fortunately there were no injuries, Deschutes County sheriff’s deputies said Thursday.

Sheriff’s Search and Rescue volunteers were near the scene when the avalanche occurred around 9 a.m. Wednesday and quickly began to investigate, said sheriff’s Lt. Bryan Husband, special services coordinator.

The avalanche released at the southeast end of the bowl, where motorized activity is permitted, Husband said.

The volunteers didn’t see how the slide was triggered, so they immediately assessed the debris area for safe access and began a search for any emergency locator beacons, then started a visual search for any signs of human activity.

No people or clues were found, so the volunteers headed to the butte’s summit for further investigation, the lieutenant said.

When they reached the summit ridge, they noticed large cracks in the snow, resulting from “snow bike” tracks along the ridge, directly above the slide, he said. A “snow bike” is a motorcycle with a ski in front (replacing the front wheel) and a track in the back (replacing the back wheel).

Husband said about 60 percent of the bowl’s snow released, traveling about a quarter-mile, “and was destructive enough to bury, injure or kill a person recreating in the area.”

Probes were used to determine the snow depth in the avalanche area, measuring about 9 feet.

“It is very fortunate no one was injured or killed as a result of this avalanche,” Husband wrote. “This is a sobering reminder of the dangers of traveling and recreating in back country/wilderness areas and in avalanche terrain, as well as the destructive force of an avalanche.”

Husband said the sheriff’s office wants to remind people recreating in those areas to have proper gear (an avalanche beacon, shovel, probe, 10 essentials for wilderness travel listed here) and training prior to” heading out.

Husband explained that an avalanche beacon “is a location transmitter device which all backcountry recreating folks are encouraged to carry with them in the winter time. They act as a locating beacon for someone searching for you, and then also serve as the searching device to find someone else with a beacon.”

He also urged backcountry travelers to check available resources such as the Northwest Avalanche Center, Central Oregon Avalanche Center and National Oceanic Atmospheric Administration “to understand and mitigate potential danger when traveling in remote and avalanche terrain.”

The Central Oregon Avalanche Center had professional snow observers in the area over the weekend and saw the potential for danger.

“We knew that there was a weak layer in the snowpack. Then we had this big storm come in on Tuesday, and it came in really wet and heavy,” board member Alli Miles said Thursday. “When you get a foot of snow and it’s really heavy like that it’s basically a perfect recipe for an avalanche.”

Miles said avalanches in Central Oregon are far more common than most people realize.

S he recommends knowing the conditions before you head out into back country, travel with at least one other person, and pack a beacon and a shovel.

David Reuss of Bend said he was in the area on his snow bike before and after the avalanche occurred. Reuss said he and his friends surveyed the area and decided it was not safe to enter the bowl, but returned shortly after the avalanche occurred.

“We came back probably 15 minutes later to meet up with one of our buddies and we were taking a break on the ridge,” Reuss said. “I looked down and said, ‘Oh my gosh, look at that.’ We were 30 feet from where we were digging our pit. And the whole thing had ripped out.”

Reuss explained that digging a pit is a technique used to see if an area is safe. The pit is dug on an open slope at about 5 feet deep, or to the ground, whichever comes first. You then make the face of the pit smooth to see if there are visible layers.

Reuss said understanding there was a weak layer in the bowl was just one indication to him it was not safe. He cautioned everyone to be aware of the dangers of potential avalanches in Central Oregon, adding that he sees them every year while out in the backcountry.