What it is
Liftie’s rating answers one question: how hard is this run? It is measured from the shape of the ground, and it uses the same scale at every mountain, so a Black at one resort means the same as a Black at another. It is free for every rider.
It is not a quality score, a fit score or a safety rating. It is not personal: every rider sees the same rating for the same run. It is not the resort’s official difficulty, which the app shows beside it.
The scale
There are four bands, and each has three steps.
| Band | Steps |
|---|---|
| Green | Green−, Green, Green+ |
| Blue | Blue−, Blue, Blue+ |
| Black | Black−, Black, Black+ |
| Double black | Double black−, Double black, Double black+ |
A minus sits in the easier third of its band and a plus in the harder third. Higher means harder, never better. Earlier builds showed a number from 1 to 10; that number is gone from the app.
Where you see it
- On the map, runs are colored by Liftie’s rating where the resort has been measured.
- On a run’s page, the Liftie card shows the rating. The resort’s own color has a card of its own.
- Tap ⓘ on the card to open “What is Liftie’s rating?”. It shows up to three reasons for the rating, how steep the steepest stretch is and where it sits on the run, and how the rating compares with the resort’s color, such as “Harder than the resort’s Blue”, “Easier than the resort’s Black” or “Same as the resort”.
What it is measured from
Each run is measured along its mapped center line on 1 m lidar terrain. These go in:
- The crux: the steepest sustained stretch of 150 vertical feet. This is the main input.
- The entrance: how steep the top 50 vertical feet are.
- Sustained steepness: how much of the run’s vertical is steeper than 25°.
- Rollovers: convex breaks where the slope steepens out of sight.
- Drops: short drops steeper than 55° count as drops, not as pitch.
- Width: at the crux and at the narrowest point.
- Trees: how much of the run is under canopy and how tight the gaps are.
- Rock and exposure: rock within about 100 ft of the line.
- Terrain type: the mix of seven terrain classes the run crosses, such as groomable slope, glades, bowl and chute.
- Groomable ground: whether the terrain is the kind that can be groomed. This is about the ground, not about whether it was groomed today.
- Above treeline: whether the run is open and exposed.
These do not go in: the run’s length, its average pitch, crowds, lift waits, rider reports, your profile and the resort’s color. The resort’s color was used once, as a weak guide, when the scale was fitted.
How it is worked out
The rating is fixed code, not an AI model. A formula in degrees starts from the crux and adds weight for each of the inputs above. Its weights were fitted once, over a few hundred measured runs, and the same weights apply at every mountain. A run is never rated easier than its crux alone would put it.
The reasons in the ⓘ sheet come from the same measurements. Examples are “steep pitch”, “narrow”, “tight trees”, “12 ft drop”, “cliff band”, “blind rollover”, “steep entrance”, “long sustained pitch”, “no-fall zone”, “groomed run” and “wide open”. The rating does not detect cornices, mandatory airs or moguls.
How today’s conditions change it
The measured rating is the run on a normal day. Each day the app adjusts it on your iPhone from that day’s conditions report and the resort’s grooming report.
| Trigger | When it applies | Effect |
|---|---|---|
| Fresh powder | 6 in or more of new snow in 24 hours | Harder on ungroomed runs, a little harder on most others. Green runs don’t change. Double blacks get a little easier. |
| Hard ice | 0.5 in of snow or less in 72 hours, and 25 °F or colder | Harder, more on steep runs. Less on a run groomed today. |
| Flat light | Visibility of 1 mile or less | A little harder on open runs. Tree runs don’t change. |
| Groomed today | The resort reports the run groomed today | A little easier, except green and double black runs. |
| Strong wind | Gusts of 35 mph or more | A little harder on open runs. |
All of today’s changes together move a run at most two bands. When a run’s rating changed, the card says so and names the biggest reason, for example “Normally Black+, changed due to hard ice”.
A lift’s rating
A lift’s rating comes from the named runs that start at its top, weighted by their length, and the lift page says how many runs it used, such as “from 6 runs off the top”. A lift is never rated easier than the easiest full way down from its top.
When there is no rating
- A resort that hasn’t been measured: the map uses the resort’s own colors, and the run page says “Liftie rating not mapped yet”.
- Terrain parks: never rated. The run page shows Feature size from XS to XL instead.
What it doesn’t tell you
The rating describes the terrain. It doesn’t know whether a run is open, how crowded it is, or what the snow is like beyond the conditions above. It is not an official difficulty or safety rating. Follow the resort’s signs, closures and ski patrol.
A personal read for how you ride is a Max feature: Liftie’s read on any run or lift. See Plans.