Multiple weather models, one honest call.
No single weather model is best everywhere in the Alps. Bluepow learns which to trust, where, and when.
Meet 4Kasta
The forecasting engine behind every Bluepow call.
4Kasta is our own model. It blends multiple weather models with the weather around each resort, the Alps-wide pattern and each resort's own history, and turns them into one bluebird or powder call. Every 4Kasta call is logged in advance and scored afterwards on our scorecard, misses included.
Powder is hard to call.
So we score every call.
1. Read every model
For each resort we take cloud, sunshine, snowfall, temperature and wind from multiple open European and global weather models, including high-resolution 2 km Alpine models.
2. Zoom out
We add the bigger picture: nearby resorts, the region, the country, and the Alps-wide pattern, such as foehn, southern stau or a blocking high.
3. Learn each resort
4Kasta, our machine-learning model, trained on five winters of past forecasts and station measurements, learns how each resort behaves in each pattern.
Why days ahead matter
Forecasts get less certain the further out they look. We train a separate model for 1 to 5 days ahead on real past forecasts made that far in advance, so the scores on our scorecard show how the forecast actually performs at each range.
Bluebird calls that came true
By days ahead. Amber line: a random day (30%).
Testing on five past winters (2021/22 to 2025/26), checked against weather-station sunshine at 321 resorts. Days 1 to 5 are the evening forecast; the morning update scores up to 3 points lower.
Does blending actually help?
Yes. On the same 281,202 resort-days, our same-day bluebird calls came true 79% of the time. ECMWF on its own (the European forecast model, and one of the models we blend), tuned to each resort in the same way, managed 70%. We also forecast more of the days that really were bluebird: 86% against 77%.
Results from testing on past winters, same-day bluebird forecasts only. ECMWF is one of the models we blend, and it does not endorse Bluepow. The scorecard has the details. See how we compare with typical forecast apps.
Same-day bluebird forecasts
281,202 resort-days, same days for both
Calls that came true
Real bluebird days forecast
Where the data comes from
Weather forecasts
- Weather models
- Ensemble forecasts
Multiple open weather models from national weather services and international forecast centres.
Observations
- Stations
- Satellite
Measured sunshine and new snow, used to check and tune every forecast.
Resorts
- Open map data
Location and elevation of every resort.
Data credits are in the footer. None of the organisations credited endorses Bluepow.
What it can’t do yet
Beyond 5 days
Forecasts more than 5 days ahead are not yet scored.
Exact snow depth
Big storms are well forecast, but telling 12 cm from 18 cm is not.
Resorts with no station
Resorts without a nearby station, mostly in Italy, get forecasts we can’t yet verify.