Reading avalanche bulletins
A plain-language guide to understanding the forecast before you leave the trailhead.
The avalanche bulletin is the most important document you read before a backcountry day. It tells you what the snow is doing, where the danger sits, and what terrain to avoid. Learning to read it is a basic skill, not an advanced one. Here is a plain-language guide.
Start with the danger rating
The rating runs from Low to Extreme, usually shown as a coloured scale. Low does not mean safe · it means the danger is isolated. Considerable is where most accidents happen, because conditions feel manageable but are not. Treat every step up the scale as a step toward simpler, gentler terrain.
Read the avalanche problems
The bulletin names the specific problems · wind slab, persistent slab, loose wet, and so on. Each one tells you something different. A wind slab problem means avoid lee slopes and corniced ridges. A persistent slab problem means the weak layer lingers for days or weeks, and you change your terrain for the whole trip. The problem matters more than the rating.
Look at the elevation and aspect
Danger is rarely uniform. The bulletin shows where the problem lives · above treeline, near treeline, or below, and on which compass aspects. A danger that sits on north-facing slopes above 2,000 metres is a very different day than the same rating spread across all aspects. Read the map, not just the number.
Check the trend
Is the danger rising, falling, or holding? A rising trend through the day means the afternoon is worse than the morning, and you plan accordingly. A falling trend means the worst is behind you, but the weak layer may still linger beneath new snow.
Make the call before the trailhead
Decide your terrain for the day at home, reading the bulletin with a coffee, not at the trailhead with your group watching. It is much harder to turn around once you are dressed, skinned up, and committed. Build the habit of a real plan, a backup plan, and a turn-around time.
The honest bottom line
The bulletin does not make decisions for you · it gives you the information to make your own. The women who come home every time are the ones who read it, respect it, and let it change their day. Read it every morning, talk about it with your group, and let the mountain set the rules.