Avalanche forecasters at this week's Arctic Man event near Paxson are warning snowmachiners of especially dangerous conditions and advising them to avoid risky behavior after a series of slides including one that killed a woman Sunday.
The Alaska Avalanche Information Center said in a statement that danger in the region had increased "dramatically" in recent weeks, even as more snowmachiners take to the slopes in the spring.
"We've seen people riding suspect slopes and avalanches ripping out on every aspect, especially wind-loaded slopes," avalanche forecaster Kevin Salys said in the statement. "In the past two days there have been several human-triggered slides with large involvement, and folks have just been lucky to get out."
A daily forecast of Arctic Man avalanche conditions on the avalanche center's website warned of persistent slab avalanches and cornice falls in the Paxson and Summit Lake areas. Forecasters advised people to steer clear of slopes greater than 30 degrees with cornices or wind-loaded snow.
"Whumphing (settling of the snow pack under you), shooting cracks and firm, hollow snow are all red flags that dangerous and unstable snow conditions exist," staff wrote. "These avalanche conditions can be very unpredictable due to the supportive nature of the upper layers.
"Once you get the right load in the right place, the failure can be dramatically larger than imagined."
Debra McGhan, a spokeswoman for the center, said in an interview Wednesday that temperatures in the 40-degree range followed by fresh snowfall have produced slabs of new powder atop a "deep consistent weak layer" of softer material.
"Underneath the snow, it's like granulated sugar; it's not cohesive," McGhan said. "It's on these ball bearings, so when the slab breaks it crumbles -- and it just keeps tumbling down."
McGhan said she's seen snowmachiners at Arctic Man this week riding their sleds into "terrain traps" -- areas with depressions formed by rocks or cliffs, where snow from a slide can become particularly deep.
Some riders have also parked their sleds to watch other people ascend, she said, leaving themselves vulnerable to slides like the one that killed 25-year-old North Pole resident Claire Sundgren near Summit Lake.
"We see people sit at the base of these hills where they think they're in the clear, and the snow comes down and they get tumbled off their sleds," McGhan said.
With light snow falling from gray skies at Arctic Man on Wednesday morning, forecasters were urging people to avoid terrain traps as well as any assumptions that traveled areas are stable.
"We tend to see tracks and think, 'Oh, someone else has been there -- it must be safe,'" McGhan said. "Just because you see tracks doesn't mean it's safe."
According to McGhan, people aren't being particularly reckless at this year's Arctic Man, but they aren't taking the current avalanche outlook into account.
"With the conditions being so tricky right now, we're seeing people do kind of the same thing they've always done," McGhan said. "They may not get away with it this time."
The center has a tent at Arctic Man and is jointly hosting avalanche awareness sessions with the Chugach National Forest Avalanche Information Center beginning at 12:30 p.m. Wednesday. A second session at 11 a.m. Friday will feature Iron Dog snowmachine race champion Tyler Aklestad.