On a marked, open, patrolled piste, no. Marked pistes are assessed and controlled by the resort, and the equipment answers a question that is being handled by somebody else.
The reason this page exists is the other half: how few metres it takes to stop being on one.
Where the line actually is
A piste is open, marked and patrolled. Everything else is not, whatever it looks like from the chair.
The strip of untracked snow beside the run is off-piste. So is the short cut between two runs through the trees. So is the bowl that a lift deposits you above. None of them becomes controlled terrain because it is close to one.
What changes when you cross it
Three things, in this order: the avalanche forecast for that area and day becomes something to have read; the party matters, because the kit works between people; and the training matters more than the equipment.
Buying a transceiver and stepping off the marked run is the wrong order, and it is the order the shelf encourages.
The intermediate cases
Ski touring on a marked route. Still not patrolled. Still avalanche terrain where the slope allows.
Resort off-piste patrolled and opened by the resort, which exists in some places and not others, and which the local rules define rather than this page.
A closed piste. Closed frequently means uncontrolled, and sometimes means being worked on. Either way it is not an open piste.
What to do with the question
If the answer is “piste only, always”, the money on this site is better spent on goggles, a helmet that fits and boots that were fitted.
If the answer is “mostly piste, but”, then the kit and the course come together, and the course comes first.
How this site prints it
Avalanche pages compare equipment on published figures — antenna count, probe length, blade material, airbag volume — and every one of them says that the equipment is the smaller half of the question. None of them tells anyone where it is safe to ski.
Where this page and a maker’s own documentation part company, the documentation is right. Every length, waist width, radius, flex index, last width, DIN range, brake width, filter category, temperature band and mass on this page comes from the maker’s own published figures, with the unit as printed and the source named. None of it is measured here, and no figure is converted into another convention, because a converted number is a different number. And the line this page does not cross: equipment is not training, and nothing here makes a slope safe. A transceiver frequency, a probe length or a stated airbag volume is what a maker published about an object. Whether a party can use it depends on practice, on the day and on decisions taken before anyone left the car park, and this page points at the course rather than standing in for it.
The questions asked most often
What about the strip of powder beside the piste?
That is off-piste, and the terrain does not know it is only twenty metres wide. Whether it is avalanche terrain depends on the slope above it, which is a question for the local forecast and the patrol.
Is a transceiver useful if nobody else has one?
Only for being found, and only if somebody nearby can search. The kit works as a party, which is why the answer to “should I buy one” usually starts with who you ski with.
Last reviewed 28 September 2026