Steamboat Springs Anyone heading into the backcountry to ski or snowmobile has to be aware of a weak snowpack that avalanche experts warn is ripe to be triggered.
Between Thursday and Sunday, four people died across the state in avalanches caused by a snowpack the Colorado Avalanche Information Center has described as the weakest in about 30 years.
"This is going to be an interesting spring," said Denny Hogan, a snow and avalanche forecaster for the information center. "The snowpack does not have the strength it usually has this time of year. We might see some big slides this spring."
The information center has determined the avalanche danger across the state to be "considerable," which is lower than "extreme" and "high" but higher than "moderate" and "low."
Because of the avalanche danger, anyone going into the backcountry to ski, snowmobile or for any other recreational purpose needs to be careful, Hogan said.
"The snow is unstable," he said. "Human-triggered avalanches on steep terrain are probable."
Jeff Hirschboeck, who has been the avalanche team leader for the Steamboat Ski Area for the past 25 years, agrees.
"Steep areas that haven't had daily compaction by skiers or snowmobilers definitely have the possibility to be triggered," he said. "In unutilized areas, avalanches are probable on steep slopes."
Throughout the ski season, Hirschboeck and his team are responsible for ensuring the ski area is safe from avalanches.
Hirschboeck and his team are able to monitor avalanche conditions by digging pits within and outside the ski area's boundaries. The last pit the team dug was March 9, and Hirschboeck did not like what he saw.
"If you find bad layers of snow within the ski area, the layers outside of the area certainly won't be good," he said.
On Jan. 6, about an inch of sleet covered Northwest Colorado, including Routt, Pitkin and Eagle counties, he said. Prior to that storm, sugar-like snow covered the ground.
"There is a soft layer of snow immediately under the sleet that is about an eighth of an inch thick," he said. "Covering the sleet is another layer of fragile snow. The sleet is acting as a bridge. This is terribly unusual."
Numerous snowfalls in March have compounded the problem, Hogan said.
"This has been a stormy month," he said. "The recent snow has provided a thick slab on top of the weaker snow. Now it is waiting for a trigger."
The human triggers have occurred in recent days and have proved to be deadly. Daniel James Ovenden, 31, of Craig was killed Sunday in an avalanche near Pagoda Peak in a remote section of Rio Blanco County. The man was snowmobiling when the avalanche occurred.
A 31-year-old San Diego, Calif., woman died in an avalanche Friday near the Telluride Ski Area. The woman was snowboarding when the avalanche occurred.
Two people were killed near Aspen on Thursday. A 39-year-old Chicago woman was killed in an avalanche while she was skiing the backside of Aspen Mountain.
A 63-year-old Fort Collins man was killed skiing in Ashcroft near Landley Hut, which is 14 miles southwest of Aspen.
With the snowpack not expected to strengthen anytime soon, Hogan and Hirschboeck warn people planning to go into the backcountry to be careful.
The two men urge people to stay off slopes that are at least 30 degrees.
"We don't want people to go out into the backcountry," Hogan said. "We want them to avoid steep slopes."
Hirschboeck said people should also stay away from areas that have not been tracked or compacted by a skier or snowmobiler.
"Anyone going into the backcountry needs to be aware of where they are and stay away from steep slopes," he said.
The two men also recommend that shovels, avalanche beacons, probes and extra clothing be taken by anyone going into the backcountry.
"The snow will be unstable for quite a few weeks," Hogan said. "But it will stabilize over time."