Colorado remains most dangerous state for avalanches

Sawyer D’Argonne
Summit Daily
Looking up the slide path from the toe of the avalanche. The crown face is obscured by the clouds at the top of the image. The avalanche was approximately 285 feet wide at the crown face and around 375 feet wide at the toe. The avalanche ran around 425 vertical feet.
Colorado Avalanche Information Center/Courtesy Photo

FRISCO — Colorado again retained its macabre status as the country’s most dangerous state for avalanches, according to data collected by the Colorado Avalanche Information Center.

Since at least 1950, the amount of avalanche deaths in Colorado have far surpassed that of any other state, and the most recent avalanche cycle was no different. The Avalanche Information Center released its annual report earlier this month, highlighting statistics from one of the most substantial avalanche seasons in the past century.

During the 2018-19 season, the state recorded 4,273 slides — 478 in the Vail and Summit County region — including 92 that caught people on their way down. In all, 135 individuals were caught in avalanches, a high water mark over at least the past decade, and eight of those people were killed, the most since the 2013-14 season. Of the seven other states that recorded an avalanche fatality last season, none had more than four.

A prolific winter from a snowfall perspective helped to drive avalanche numbers. Colorado’s snowpack peaked April 5 at 133% of the state’s 30-year median. Likewise, Summit County recorded higher than normal snowfall levels. According to the Avalanche Information Center, from November through April, Arapahoe Basin Ski Area recorded about 104% of its average snowfall, Breckenridge Ski Resort recorded 161% of average, Copper Mountain Resort recorded 118% of average, Keystone Resort recorded 115% of average and Loveland Ski Area recorded 117% of average.

But looking back over the past 70 years, it’s clear that the trend of heightened avalanche danger around the state isn’t a recent phenomenon. Since the 1950-51 season, Colorado has recorded 287 avalanche fatalities, easily dwarfing other danger areas like Alaska (158), Washington (130), Utah (120) and Montana (119).

One explanation for the state’s elevated avalanche danger is certainly the number of recreationists heading out to Colorado’s backcountry.

“That makes a huge impact,” said Avalanche Information Center Director Ethan Greene. “The more people you have exposed to avalanche hazards, the more chances you have of someone getting involved in an avalanche. We have a huge winter recreation industry and culture in Colorado. We have about 27 major ski areas. We have highways that run through the mountains, a lot of people that live in the mountains, and people who visit us to play in the mountains. So there are a lot of people trouncing around in the woods.”

The rise of the backcountry recreation culture nationally helps to shed some light on more recent trends in avalanche fatalities. For example, in the 1980s, there was an average of just 14.3 avalanche fatalities per season compared with 25.6 in the past decade. In 2018-19, 12 of the nation’s 25 avalanche deaths were individuals out backcountry touring and eight were snowmobilers.

But an increase in popularity in backcountry recreation doesn’t help to explain why Colorado alone suffers so many more avalanche deaths historically than anywhere else in the country. According to Greene, the state’s unique snow climate often creates less predictable avalanche conditions than in other mountainous areas around the country. In most areas, avalanche danger tends to spike and stabilize quickly following a storm, but in Colorado, weather events can create lingering instability for weeks.

“The weak layers that we get are what you’d call persistent weak layers,” Greene said. “They’re formed from dry, clear and calm weather conditions. But those can cause us problems for days, weeks and sometimes months. They can happen in other parts of the United States, but they’re less common. We’re dominated by three main things: high elevation, we’re far away from oceans, and we have a lot of wind.

“We’re farther away from a major moisture source, and we tend to have a shallower snowpack. Our snowfall tends to be lower density, our air tends to be colder, and we have a lot of wind. You can get a lot of wind in the coastal mountains, too, it just tends to be more dramatic individual events and not as consistent. … We have tricky avalanche conditions more often than a lot of other areas.”

Despite some similar conditions to last season, Greene again noted that its unlikely the state will be hit with another historic avalanche season.

“We certainly hope the 2020 season isn’t going to stack up to the 2019 season,” Greene said. “But we do have some very similar conditions in the snowpack right now to what we did this time last year. We have a very weak basal snowpack, which is why we’ve seen so much avalanche activity over the last month. And how that plays out over the next couple months really depends on what kind of weather events we get.

“There is a storm headed our way later this week, so you can expect the avalanche danger to rise with more snow and wind. But in general the avalanche hazard has been dropping over the last few days, and we hope it’s going to be a really fun and safe holiday season for everyone living here and visiting.”