Spring Hazards

Full disclosure or true confessions, I love the Cascades so much my wife considers herself a widow from Mid-March to Memorial Day. The Spring Equinox means longer days, a settling snowpack, and longer tours. In the Northwest we look to the high alpine for long descents off the volcanoes, touring into the North Cascades and Olympics. Unforgettable high alpine traverses get done under long sunny days but there’s a catch – avalanches. Very dangerous avalanche conditions surprise us when we’re expecting to reap the rewards of a long winter. The risks we encounter center around decision making and communication regarding our ability to actually see the transitional nature of the snowpack. Not to mention, our willingness to take more risk under warm, sunny skies.

Spring Haz 3Recent accidents in Washington and Colorado show that even high levels of education cannot prevent human errors. When trust creates the sense that everyone is thinking the same thing errors occur. People describe complete trust as not requiring communication. This doesn’t work in a complex environment such as a transitioning snowpack in challenging terrain. The wide range of variables in the backcountry requires everyone to express both their personal and environmental observations. This free exchange of information keeps everyone engaged in risk management, which increases trust, not undermine it.

The other error educated and experienced people make is not recognizing that their actual experience may not include extraordinary conditions that exceed what they’ve witnessed before (aka, the Confidence Curve). Say you toured for two to four seasons and rode a variety of terrain; you might not have witnessed remote triggering, deep slab releases,, and surface hoar human triggered D 2.5 or larger avalanches. This relates to the confidence curve, which is reset when you personally experience one of these events. These avalanches usually surprise us by exceeding what we anticipated of the terrain. Hopefully this only results in a near miss or minor injuries along with a new awareness of what can happen.

BR SPring Haz 4The Ides of March bring a deeper level of stress to winter snowpack in the form of Solar Radiation. During longer days, heat and more direct solar input to the snowpack add stress to the surface and mid-pack as melt water percolates into older layers and breaks down bonds. The rapid addition of heat to a winter snowpack that’s still holding a variety of layers increases instability.

Spring rain adds another dose of heat and stress to the snowpack altering stability. Showers arrive with warm air and create dangerous isothermal conditions at lower elevations where the entire snowpack loses cohesion. The increase of heat from rain can cause New Snow Avalanches, Wet Loose Snow Avalanches, and Deep Wet Slab Avalanches (Climax slides).

BR Spring Haz 1Timing is a vital part of your travel plan as the South/Southeast aspects heat up in the early morning and can begin shedding around 10:30 to 11 am and continue around to the southwest aspects by early afternoon. In the Rockies, spring storms bring warmer, denser snow that adds larger loads to fragile snowpack creating a threat of large avalanches like the Sheep Creek slide at Loveland, CO.

High alpine descents and traverses require calculated timing and a reasonable weather window. Ice falls occur on glaciers a result of glacier motion. They’re triggers for large and deep avalanches because the ice can weigh thousands of pounds and fall great distances. Snowfall in the alpine zone happens year round (above tree line which varies from the coast to the Rockies) and white outs increase the hazard due to loss of visibility. These natural factors increase risks that require immense planning and timing when touring the backcountry.

Options and several exit routes are a necessary part of planning. I often look at my objectives and select several on both sides of the Cascade Crest to use the rain shadow to give me a “bad weather option” if conditions look warm and wet.

BF Spring Haz 2The necessary equipment for touring during spring includes several items that help manage the melt/freeze surface conditions:

  • Ski Crampons allow you to engage your skins on firm crusts and continue to skin versus continuing on foot.
  • Boot Crampons allow you to climb in the early morning on glacial terrain and firm snow safely.
  • Ice axes are used on terrain steeper than 35 degrees. One axe is necessary to ensure you have a tool capable of swinging into ice or nerve.
  • Whippets work well but are optional as they don’t completely replace an axe.
  • GPS is recommended for long trips above tree line.

Avalanche danger exists well into spring and we all need to remain attentive to issues that arrive when making decisions. We need to understand we can never know everything and that trust should improve conversation – not negate it.

– Matt Schonwald

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