The Swiss avalanche bulletin is issued daily at 5 pm, and in midwinter also at 8 am. It is free, it is one of the best in the world, and most people use it wrongly: they open it, see a number and a colour, and close it again.
They have read the least important part.
Why the level alone is no use
- 1 low
- 2 moderate
- 3 considerable
- 4 high
- 5 very high
A danger level applies to an entire warning region, that is, an area the size of a valley or larger. Within that region there are slopes where essentially nothing can happen that day, and slopes that are critical. The level says how much of each there is, not where.
That is exactly what the entries beneath it cover. They are the real content of the bulletin, and they cost less than two minutes more.
The four things that matter
The avalanche problem
The European avalanche warning services distinguish five typical problems, and they behave completely differently. This is the single most important entry in the bulletin, because it determines what you can observe at all.
| Problem | Behaviour | Recognisable |
|---|---|---|
| New snow | breaks down in days | yes, by the amount |
| Wind slab | breaks down in days to weeks | yes, by wind and deposits |
| Persistent weak layer | lasts weeks to months | no |
| Wet snow | depends on time of day, better at night | yes, by temperature and snow |
| Gliding snow | unpredictable in timing | yes, by cracks in the slope |
The same “considerable” means something quite different for wind slab and for a persistent weak layer. With wind slab you know where to look and can avoid the affected slopes. With the persistent weak layer problem you cannot, because there are no signs at the surface.
The aspect rose
A circle marked with the compass points, with the critical sectors shaded. It answers the question of which way the dangerous slopes face.
This is not a detail but often half the information. If the rose covers north through east, south-facing slopes are a different world that day, and the reverse.
The elevation band
Almost always the bulletin states an elevation above or below which the assessment applies. “Above 2200 m” means a different, usually lower danger below it.
Combined with the rose this produces a strikingly concrete statement: not “it is dangerous today” but “critical are north- to east-facing slopes above 2200 metres”.
The time of issue
The 5 pm bulletin applies to the following day. If new snow falls overnight or it turns unexpectedly warm, it is out of date by morning. That is why there is an 8 am issue in midwinter, and why “when was this written” is not a formality.
With wet snow there is the added point that danger increases through the day. An assessment that holds in the morning can be wrong by the afternoon.
The Swiss sub-levels
Since the winter of 2022/23 the SLF has additionally stated, from level 2 upwards, where inside the level you stand: 3− at the lower end, 3= in the middle, 3+ at the upper end. This applies only to dry avalanches and exists so far only in Switzerland.
The reason is that level 3 covers a very broad band. Between 3− and 3+ lies what amounts to the distance of a whole level. More on that in our piece on the five avalanche danger levels, including the figure showing why level 3 of all levels claims the most victims.
The order
Read the bulletin this way and you get more out of it in two minutes than in ten seconds on the colour:
- Which problem? It determines everything else.
- Which aspect and above what elevation? That turns it into a statement about terrain.
- Which level, and with which sub-level? Now the number has a context.
- When was it written, and what has changed since? New snow, wind, warmth.
- Read the text. The prose beneath the symbols is where the forecasters say what they are unsure about.
Point five is skipped most often and is the most honest part of the whole document. It carries sentences like “the danger spots are hard to recognise” or “individual avalanches can become large”. Those are not filler but the uncertainty assessment of the people who wrote it.
What the bulletin does not do
It does not assess an individual slope. It cannot, and it nowhere claims to. Between “critical are north-facing slopes above 2200 metres” and the decision whether this particular slope holds right now lies the entire part that requires training.
Nor does it replace observation. It is built from measuring stations, observer reports and models, at a spatial resolution coarser than any terrain you actually stand in.
The bulletin is a very good starting point. It is not a decision.
Sources and caveats
- SLF, avalanche bulletin: issued daily at 5 pm for the following day, and in midwinter additionally at 8 am. Structure of danger level, avalanche problem, aspect rose, elevation band and text section.
- SLF, subdivision of danger levels, introduced for the winter of 2022/23, from level 2 upwards and for dry avalanches only. As of our information in August 2026, in operation only in Switzerland.
- EAWS (European Avalanche Warning Services), common danger scale and the five typical avalanche problems: new snow, wind slab, persistent weak layer, wet snow, gliding snow.
- The notes on how each problem breaks down and how recognisable it is summarise the usual presentation of the warning services. They are an orientation, not a rule by which individual slopes can be judged.
This piece explains the structure of a document. It is not training and does not replace an avalanche course; translating the bulletin into terrain is learned with the SLF and the SAC.
