How we collect data

This season

We check each resort’s official lift-status page automatically a few times a day. The number and times of checks vary by day, and each page shows when it was checked.

Status and confidence are separate

We keep the status (open, temporarily stopped, not scheduled and so on) separately from how we learned it (confidence). A “stopped” confirmed on the official site and a “stopped” we estimated are shown differently.

Stop times

We only know what changed between two checks, so we write a range such as “stopped between 10:30 and 12:00”. On days with fewer than three checks we write “Stopped (time unknown)”, never “Stopped all day”.

Last five seasons

Records collected from official notices of the time, official pages kept by the Internet Archive and third-party records. Grade B and C sources cannot confirm stops or “not scheduled”, so those days show “No record”.

Confidence

Six levels: observed, official schedule, A confirmed, B mostly confirmed, C estimated and SNOLIO estimate. A day’s confidence is the lowest of its time bands.

Estimates

An estimate has not been confirmed as fact. Estimated values carry an “Estimate” label and never look like facts. We never estimate that a run is open. We may infer that a lift is running from the state of the runs it serves, and label that as an estimate too.

Sources

Each row shows one representative source; open the row to see every source and check time.

Times

All times are Japan time. Nothing is real time; each value is as of the time it was checked.

Weather

We do not handle weather information at the moment.

If SNOLIO differs from the resort’s official website, the official website wins.