“Would you step off a cement curb onto a busy city street with a paper bag over your head?” Blaine Smith asks his audience. “Venturing into Alaska’s backcountry without any knowledge of the avalanche danger is no different.”

In a lively, one-hour presentation at the Eagle River Nature Center on November 20, avalanche expert Blaine Smith described different kinds of avalanches and the conditions that cause them. An instructor with the Alaska Avalanche School, a non-profit organization, Smith has amassed a significant amount of knowledge regarding backcountry travel during his nearly 40 years in Alaska.

Smith noted that per capita, Alaska is number one in avalanche fatalities and that 95 percent of those avalanches are triggered by the victims themselves – motorized and/or non-motorized. Victims are most frequently males in their mid-20s.

The primary causes of death in avalanches, Smith says, are trauma – such as collision with rocks, trees and other objects – asphyxiation nd suffocation.

Readers can view a video that illustrates how quickly an avalanche can be triggered, how large of an area it can cover and how fast the avalanche travels at the following URL:

https://www.youtube.com/watch?v=BpNxRsIoN58

Here are the things one should look for when in the backcountry:

While ice falls, loose snow, cornice falls and even snow sliding from building roofs can present objective dangers, Smith says slab avalanches pose the most trouble for winter recreationists. In such an event, a relatively cohesive layer of snow overlies a weaker layer – sometimes across a wide area of the the slope – and breaks away.

Terrain, snowpack and weather all factor into assessing conditions that contribute to slab avalanches. Smith says it’s important how we use knowledge, experience and judgment to evaluate those conditions.

“Slope angle is extremely important,” Smith says. “Slab avalanches are common at angles between 35-40 degrees, with 38 degrees the most predominant. We can visually measure slope angles, but we can also back that up with a compass measurement.

“Current avalanches are the best sign they will occur in area in the near future,” he continues. “And always be mindful of the weather. Warming weather quickly causes snowpack instability.”

Smith advises that recreationists should also be on guard for small valleys, or depressions in the terrain that can become terrain traps during an avalanche – piling up high at the deposition, or “run out” zone.

He adds that wind loads the ridges with snow, creating cornices and that moving above or beneath them should be avoided.

Smith also advises testing the stability of snow layers on little slopes by digging a pit. Examining how the layers of snow adhere to one another is key to understanding the nature and causes of avalanches, he mentions.

“The “whoomf” sound of snow settling and releasing air is a warning that you are on an unstable slope,” he says.

“If you like to venture into the backcountry in winter, I advise gaining as much knowledge as possible to heighten your avalanche awareness,” Smith says. “But if you’re unsure of your ability to assess avalanche danger, it’s best to avoid those areas altogether. Decision-making is crucial.”

Following the program, which was attended by about 45 people, Smith offered a presentation on the rescue of avalanche victims.

For more information on avalanches, go to the Chugach National Forest Avalanche Information Center at:

//www.cnfaic.org/advisories/current.php

To sign up for an avalanche course through the Alaska Avalanche School, go to:

//www.alaskaavalancheschool.com

Frank E. Baker is a staff member of The ECHO News and freelance writer who lives in Eagle River.