Safety
SAIS
Also called: Scottish Avalanche Information Service
Definition
The Scottish Avalanche Information Service issues daily avalanche forecasts for six Scottish mountain regions during the winter season (typically mid-December to mid-April). Each daily forecast covers avalanche hazard level (low / moderate / considerable / high / very high), unstable slope aspects, snowpack stability and weather influences.
Etymology & origin
Founded in 1988 after a series of fatal Scottish winter avalanches highlighted the need for a daily forecast service modelled on European Alpine practice. SAIS originally covered only the Cairngorms and Glencoe; the network expanded through the 1990s to cover the six current regions. Funded by Sportscotland and operated by professional forecasters who undertake daily field observations.
Context & usage
The six SAIS regions are Northern Cairngorms, Southern Cairngorms, Glen Coe, Lochaber, Creag Meagaidh, and the Northern Highlands. Each region has a dedicated forecaster who produces the daily report from field observation plus weather inputs. Forecasts are typically issued by 4pm for the following day.
The SAIS avalanche hazard scale is the European five-level system: Low (1) means the snowpack is generally well-bonded; Moderate (2) means caution required on certain slopes; Considerable (3) is the most common winter day at Considerable or higher; High (4) and Very High (5) are infrequent but real Scottish conditions. Each forecast specifies which slope aspects (north-east-facing, etc.) and which altitudes carry the danger.
Reading the SAIS forecast is non-negotiable for any winter Munro day. Avalanche fatalities in Scotland average 1-3 per year; many involve walkers who didn't read the forecast or who underestimated terrain risk. The forecast is free, takes 2 minutes to read, and is the single most important piece of preparation for a winter day in the Scottish hills. Glenmore Lodge runs the standard introductory Be Avalanche Aware course; book one before your first solo winter Munro.
Related terms
MWIS
The Mountain Weather Information Service is the standard daily mountain weather forecast for Great Britain. MWIS produces region-specific forecasts focused on what matters to walkers: wind speed at altitude, cloud base, freezing level, visibility and precipitation type. Forecasts are issued by 4pm for the next 48 hours.
Winter Munro
A Winter Munro is a Munro climbed in winter conditions — snow on the ground, ice on rocks, and the technical demand for ice axe, crampons and avalanche awareness. Scottish winter conditions typically run November to April, with the peak season December-March. Winter ascents account for the highest-risk Scottish walking outings.
Where to next
Reviewed 2026-05-28