Typical operating window
February–AprilSnow builds through autumn and winter, but commercial timing varies sharply between maritime and interior ranges.Verified planning context
Snow, weather and avalanche context
Historical patterns help you compare trips. They do not predict your week or replace the operator's daily decisions.
Strongest comparable snow evidence
218 mm SWE median · 158–241 mm interquartile rangeAlaska catalogue reference ERA5-Land grid cellTier C · modelled estimate · low confidenceSnow character
transitionalAlaska spans maritime, transitional, and continental snow climates. Treat statewide snow descriptions as planning context only.Public avalanche information
Alaska public forecast-center directoryCoverage is discontinuous. Match the operator tenure to a staffed forecast zone before using any bulletin.Weather and flight context
Gulf storms, Arctic air, and large terrain barriers create exceptional regional variability.
- Unstaffed weather gaps
- Coastal storms or interior cold
- Flat light across alpine terrain
Meteorological reference area
Broad Alaska catalogue locations
- Includes
- Alaska programs not assigned to Chugach or Tordrillo profiles.
- Excludes
- Chugach destination 25 and Tordrillo destination 33.
- Elevation
- No verified operator-terrain elevation band is public. Each evidence value retains its site elevation.
Evidence pack
Measurements, claims and gaps stay separate.
Tier CModelled snowfall water equivalent218 mm SWE median · 158–241 mm interquartile range
- Site
- Alaska catalogue reference ERA5-Land grid cell · 63.6000, -154.5000 · 1.3 km from Alaska catalogue reference reference point
- Period
- Calendar years 1991–2020
- Completeness
- 360 monthly means; all 30 calendar years contain 12 values.
- Method
- ERA5-Land monthly mean daily snowfall accumulation was multiplied by calendar days and 1,000, then summed by calendar year.
- Limitation
- Alaska is too large for one mountain climate value. Only named subregion evidence is eligible. This unadjusted 0.1° reanalysis grid cell is not an observation, snow depth, or terrain-wide total. Grid elevation and wind redistribution can cause substantial local bias.
- ERA5-Land monthly averaged data from 1950 to presentCopernicus Climate Change Service · accessed 2026-08-26
Monthly evidence
Each cell keeps its measurement type and unit. Reanalysis water equivalent is not snow depth. Text-only cells preserve a representative data gap.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 19.2 mm SWE | 20.4 mm SWE | 18.3 mm SWE | 17.9 mm SWE | 1.8 mm SWE | 0 mm SWE | 0 mm SWE | 0 mm SWE | 2.4 mm SWE | 23.9 mm SWE | 28.3 mm SWE | 26.9 mm SWE |
Commercial operator assessment
Operator assessment process not independently verifiedThe operator must assess current snow, avalanche terrain, weather, aircraft limits, and rescue options. No private operational plan is inferred.
Sources and evidence notes
- U.S. Climate Normals 1991–2020NOAA National Centers for Environmental Information · accessed 2026-08-25
- ERA5-Land hourly data from 1950 to presentCopernicus Climate Change Service · accessed 2026-08-25
- Published operator and trip inventoryHeliski International editorial team · accessed 2026-08-25
- ERA5-Land monthly averaged data from 1950 to presentCopernicus Climate Change Service · accessed 2026-08-26
- Alaska avalanche forecast centersAvalanche.org · accessed 2026-08-25