How It Works

Our Technology

The science behind finding your next powder day. Four weather models read side by side, elevation physics for every zone, and a confidence score that admits when the models disagree.

Multi-Model Ensemble

ECMWF, ICON, GFS and Arpege, read side by side. Each metric leans on the model that handles it best.

Elevation Physics

Temperature lapse rates and orographic effects are applied to each elevation zone.

Honest Confidence

A confidence score built from model agreement, lead time and coverage. Disagreement is shown, not averaged away.

Powder Score

The Powder Score is our flagship 0-100 index that tells you at a glance whether a resort is worth the drive. It's designed to prioritize fresh powder while penalizing conditions that would ruin your day.

Score Components

  • Base: 48h snowfall — Primary driver. More snow = higher score.
  • Bonus: Cold temps — Temperatures below -3°C at mid/top elevations add points for better snow quality.
  • Penalty: Rain risk — Calculated using freezing level vs. base elevation. Rain at base = significant penalty.
  • Penalty: High wind — Sustained winds above 40 km/h reduce the score due to lift closure risk.

The final score maps to our verdict system: Go (65+), Good (40-64), Borderline (20-39), or Skip/Wait (below 20).

Hybrid Weather Model

No single weather model is perfect. We use a hybrid approach that cherry-picks the best data from multiple sources:

ECMWF IFS

High-resolution precipitation data. Best for snowfall amounts.

GFS

Freezing level heights and vertical atmospheric profiles.

ICON

European high-resolution model for Alpine accuracy.

Data Pipeline

Weather APIsFetchProcessingOutputGFSECMWFICONOpen-MeteoAPICache(3h TTL)ElevationAdjustmentOrographicPowderScoreVerdicts

Data is refreshed every 3 hours via our automated pipeline, which fetches 16-day hourly forecasts from Open-Meteo and caches them for fast access.

Elevation-Based Estimation

Most weather APIs provide point forecasts, but ski resorts span 1000+ meters of elevation. We apply meteorological estimation models to calculate conditions at each elevation zone.

Key Techniques

  • Temperature Lapse Rate: We apply a 0.6°C drop per 100m of elevation gain to estimate temperatures at summit, mid-mountain, and base.
  • Orographic Correction: During active precipitation, we lower the effective freezing level by 100-300m to simulate mountain-induced cooling.
  • Snow Depth Gradient: Estimated using +20cm per 100m elevation gain, adjusted for temperature-based melt.
  • Rain/Snow Transition: We use a ±400m transition zone around the freezing level for realistic alpine variability.

Estimated values are marked with a ~ prefix and "est." label to distinguish them from measured data.

Model Consensus

No single weather model is best at everything, so we do not pick one. Four global models are fetched for every resort and combined per metric. Here is how it works:

Pipeline Overview

  1. Four models, hourly: ECMWF IFS, ICON, GFS and Meteo-France Arpege, pulled through Open-Meteo for each resort and refreshed on a schedule.
  2. Expert weighting per metric: Inside 48 hours the specialist model counts double for its metric: ECMWF for precipitation and snowfall, ICON for wind, snow depth and freezing level. Beyond 48 hours ECMWF counts double for everything.
  3. Elevation adjustment: The consensus is adjusted for each resort's base, mid and summit elevations using lapse rates and the freezing level, so snow at the top and rain at the base are both reported.
  4. Confidence score: Model agreement (the spread between the four), lead time and how many models reported combine into a 0-100 confidence figure shown alongside every forecast.

Snow type

Fresh snow is classified from mid-mountain temperature, humidity and wind at the time it falls: powder, dry, packed, wet, windblown or mixed. It is a physical read of what is coming down, not a promise about what is on the ground.

Frequently Asked Questions

Weather data sourced from Open-Meteo (ECMWF, ICON, GFS, Arpege). Forecasts are refreshed on a schedule several times a day. All forecasts are estimates - always check official resort sources before heading out.