How the Powder Score Works: The 3 Factors Behind Every Rating

Every day of the 10-day forecast, at every resort Powder Mission tracks, gets a single number from 0 to 100 — the Powder Mission Powder Score. This post is the plain-language version of the full methodology: what goes in, why those three things and not ten, and how to read the number like someone who's been burned by raw snowfall forecasts before.

Why one number at all?

Because the alternative is six browser tabs. Snowfall here, freezing level there, wind on a third site, and you triangulating at 11pm trying to decide whether to book. Any experienced powder chaser is already running a mental model that blends those inputs — the score just runs it consistently, across 200+ resorts, four times a day, without wishful thinking.

The design constraint that matters: the score has to answer one question — is this a day worth travelling for? It is not a snow report, not a resort rating, and not a substitute for the avalanche bulletin. It's a triage tool for deciding where to look next.

Factor 1: fresh snowfall — the headline

Forecast fresh snow for the day, in centimetres, at the resort's summit. The scale is deliberately non-linear: the jump from 5 cm to 15 cm transforms a ski day, while the jump from 60 cm to 90 cm mostly just moves the goalposts on what you brag about. So the subscore climbs steeply through the range that changes your day (10 cm scores about 51, 15 cm about 66, 25 cm about 83) and flattens out at the top — 60 cm and 90 cm are both simply all-time.

Factor 2: temperature — is the snow any good?

The same forecast centimetres can be blower or cement, and the day's maximum air temperature at summit elevation is the best single predictor of which you get. Cold air means low-density, dry snow; air near freezing means heavy, wet snow; a couple of degrees above freezing at the elevation you're skiing means the model's "snowfall" is really rain. The subscore is 100 at −7°C and below, drops to the mid-50s at 0°C, and collapses above +2°C — because past that point the day is a write-off no matter how big the number next to the snowflake icon is.

Factor 3: wind — will you be able to ride it?

Two things kill a powder day while it's still snowing: lifts going on wind-hold, and wind stripping the fresh snow off exposed faces and loading it into slabs. The wind subscore holds near 100 below 15 km/h, slides through the 40s as sustained winds pass 45 km/h (when upper mountains start closing), and heads toward zero as winds approach storm force, with an extra penalty for violent gusts.

How they combine — and why multiplication matters

Snowfall sets the ceiling; quality and wind multiply it down. That's the crucial design choice: a huge dump with terrible temperature or unrideable wind must not average out to "pretty good". A 40 cm day at +2°C scores in the 30s, not the 70s. At the same time, quality and wind can only cap the score, never zero it — a real storm always registers.

Two more honesty mechanisms sit on top. Any liquid rain at summit applies a further hard knock. And the top of the scale is tapered so that 90+ stays genuinely rare: an excellent day reads Firing (65–81); All-Time (82+) is reserved for days where deep snow, cold air, and calm winds all line up at once. If everything scored 95, nothing would mean anything.

From days to destinations

A resort's overall 10-day score is not an average, because powder chasing isn't about averages — one all-time day beats a week of dustings. The rollup leans on the single best forecast day, lifted by total snow and the count of quality days behind it, and surfaces the best contiguous storm window so you know when to fly, not just where. That's what powers the live top-20 ranking.

What the score deliberately ignores

Lift status, road closures, avalanche danger, crowd pressure, and aspect-by-aspect wind loading. Resort pages do flag one adjacent trap — days when the freezing level sits well above the base, so a summit dump can be valley rain — but the score itself stays a pure weather signal. Check the resort's operations page and the local avalanche bulletin before you commit; the score tells you where the storm is delivering, and that's all it claims to do.