nakas/powderbench-truth

PowderBench daily snowfall truth

The quality-controlled daily new-snow values that PowderBench — the live mountain-snowfall forecasting benchmark — scores forecasts against, for every station-network league. Train on it, verify against it, then go beat the weather models live.

League	Stations	Days	Station-days	Source & licence
stations	996	2015-10-01 → 2026-10-19	3,941,296	NRCS SNOTEL and SNOLITE (USDA) — US public domain; California DWR CDEC — public; BC Ministry of Environment snow pillows — Open Government Licence – BC
observers	1,158	2016-10-01 → 2026-10-16	4,247,544	NOAA GHCN-Daily (NWS COOP: public domain; CoCoRaHS: CC BY 3.0, © CoCoRaHS) and Environment and Climate Change Canada (Open Government Licence – Canada)
alps	216	2000-10-01 → 2026-10-18	2,055,024	WSL Institute for Snow and Avalanche Research SLF — CC BY 4.0, www.slf.ch

Columns: station_id, date (station-local day), snow24_in (new snow, inches; NaN when voided), valid, qc_flag (ok, missing, implausible_jump, no_swe_support, source_qc_failed, …). Station metadata (coordinates, elevation, region, featured/network tier, fitted observation-day offset) in each <league>_stations config.

How the truth is built (all code in the repo):

• stations — snow-depth deltas at SNOTEL, SNOLITE, CDEC and BC snow pillows, voided on missing/absurd depths, >48" jumps, big jumps without an SWE increase (or a neighbour's, for SNOLITE), implausible density, stuck sensors and spikes (CDEC uses the hourly reading at local midnight).
• observers — measured new snow from observers' snowboards; each station's observation-day offset is fitted against ERA5 and ambiguous stations are excluded (docs/DATA.md).
• alps — SLF's measured 24h new snow (HN) at manual study plots and IMIS stations, same per-station attribution.

Every source keeps its licence: cite the original providers listed above when you use the data. Suggested splits are by season (never random — neighbouring days are strongly correlated).