When it starts
Alta, Dec 31, 2025–Jan 5, 2026: the model's run on the day said 8.3" skiable over 6 days, best Monday at 3.9" (Nice day); the Atwater SNOTEL pillow gained 26" of depth. Model shy.
Model shy by 17.7". The usual direction: the 2025–26 backtest ran low on storm days.
Pack going in: 24" on Dec 30, 24" on Dec 31. The storm total counts from the first reading, so snow after 5pm the night before is in it.
| Day | Call | First chair | On hill | Skiable | Starts | Pillow before | Pillow after | Gain |
|---|---|---|---|---|---|---|---|---|
| Wed Dec 31 | Stay home | 0.0" | 0.0" | 0.0" | — | 24" | 28" | +4" |
| Thu Jan 1 | Stay home | 0.0" | 1.1" | 1.1" | ~4pm | 28" | 32" | +4" |
| Fri Jan 2 | Nice day | 3.1" | 0.0" | 3.1" | ~5pm Thursday | 32" | 31" | -1" |
| Sat Jan 3 | Stay home | 0.0" | 0.0" | 0.0" | — | 31" | 42" | +11" |
| Sun Jan 4 | Stay home | 0.0" | 0.1" | 0.1" | — | 42" | 53" | +11" |
| Mon Jan 5 | Nice day | 0.9" | 3.0" | 3.9" | ~7am | 53" | 50" | -3" |
Model: the run on the day (Open-Meteo Previous Runs, best_match). PowHound does not keep superseded live forecasts, so this is not the number you saw the night before. It is usually closer.
Clocks, local time: first chair 5pm–8am, on hill 8am–5pm, skiable is both. Stay home under 2", Nice day 2–8", Full Send 8" or more.
Pillow: snow depth at the Atwater SNOTEL station, read once a day around midnight. A day's gain is the next midnight reading minus that day's, so it runs midnight to midnight, not 5pm to 5pm. Depth is not snowfall: new snow settles and blows around, so the pillow usually reads under what fell. Not the resort report.
Verdict: close is within 3" or 30%. Season numbers and method: llms.txt.