If you ever plan to leave the groomed, avalanche-controlled boundaries of a ski resort to venture into the backcountry, understanding how to read an avalanche forecast is the most important skill you can possess.

Avalanche forecasting centers (like the CAIC in Colorado or the NWAC in the Pacific Northwest) issue daily bulletins detailing the current danger levels. Here is a brief overview of what those danger ratings mean.

The 5-Point Danger Scale

  1. Low (Green): Natural and human-triggered avalanches are unlikely. Travel is generally safe, but you should still watch for isolated unstable areas, particularly on extreme slopes.
  2. Moderate (Yellow): Natural avalanches are unlikely, but human-triggered avalanches are possible. You must evaluate the snowpack and route carefully and identify features of concern.
  3. Considerable (Orange): Natural avalanches are possible, and human-triggered avalanches are likely. This is statistically the most dangerous rating because the danger is high enough to be triggered easily, but not so obvious that people stay home. Dangerous avalanche conditions exist.
  4. High (Red): Natural and human-triggered avalanches are very likely. Travel in avalanche terrain is not recommended.
  5. Extreme (Black): Widespread natural and human-triggered avalanches are certain. Avoid all avalanche terrain.

Understanding Avalanche Problems

Beyond the overall rating, a forecast will specify what kind of avalanche problem exists. Different problems require different travel strategies:

  • Wind Slabs: Formed when wind transports snow onto leeward slopes. They are usually found near ridgelines and are highly reactive to human weight.
  • Persistent Weak Layers (PWL): A buried layer of sugary, faceted snow. These are dangerous because they can persist for months and trigger surprisingly large avalanches from a distance.
  • Wet Avalanches: Common in the spring, these occur when the sun rapidly warms the snowpack, causing it to lose cohesion and slide.

Disclaimer: Reading a forecast is not a substitute for proper training. Never enter avalanche terrain without taking an AIARE 1 course, carrying a beacon, shovel, and probe, and traveling with a trusted, educated partner.