Typical operating window
February–AprilGulf of Alaska storms build a deep winter snowpack; heli-ski programs focus on late winter and spring daylight.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
866 cm median · 690–952 cm interquartile rangeNOAA GHCN station USW00026442, Valdez WSOTier B · observed reference · low confidenceSnow character
maritimeMaritime storms can deliver dense snow and rapid loading. Cooling and clear weather may improve surface quality without removing deep hazards.Public avalanche information
Chugach Avalanche Center and Alaska forecast directoryCNFAIC covers Turnagain-area zones, not every Valdez or Chugach tenure. Confirm geographic coverage.Weather and flight context
Moist Gulf storms collide with steep coastal terrain, producing heavy snowfall and abrupt visibility changes.
- Coastal storm cycles
- All-alpine flat light
- Strong ridge wind and turbulence
Meteorological reference area
Valdez and western Chugach catalogue area
- Includes
- Valdez, Thompson Pass, and named western Chugach evidence.
- Excludes
- Turnagain, broad Alaska, and Tordrillo evidence unless a source states coverage.
- 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 BCoastal gateway reference-station snowfall866 cm median · 690–952 cm interquartile range
- Site
- NOAA GHCN station USW00026442, Valdez WSO · 61.1303, -146.3517 · 29 m · 44 km from the Thompson Pass catalogue reference (61.1980, -145.5527)
- Period
- July–June snow years, 1991/92–2012/13 within the 1991–2020 window
- Completeness
- 21 complete snow years; the series ended before the standard period finished.
- Method
- Quality-flagged daily SNOW values summed by snow year; incomplete years excluded.
- Limitation
- The low coastal station is not Thompson Pass or heli-ski terrain and cannot validate a tenure total.
- Global Historical Climatology Network DailyNOAA National Centers for Environmental Information · accessed 2026-08-25
Tier CModelled snowfall water equivalent — Thompson Pass catalogue area1,311 mm SWE median · 1,120–1,375 mm interquartile range
- Site
- Thompson Pass catalogue area ERA5-Land grid cell · 61.2000, -145.6000 · 2.5 km from Thompson Pass catalogue area 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
- This reference area supports evidence discovery and comparison. It is not an operating-area or tenure boundary. 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
Tier CModelled snowfall water equivalent — Valdez1,517 mm SWE median · 1,266–1,654 mm interquartile range
- Site
- Valdez ERA5-Land grid cell · 61.2000, -146.3000 · 8.1 km from Valdez 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
- This reference area supports evidence discovery and comparison. It is not an operating-area or tenure boundary. The sampled gateway cell can differ substantially from ski elevations. 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
Tier EPublished commercial snowfall claim500+ in / 12.7+ m operator claim
- Site
- Thompson Pass and Tsaina Valley near Valdez
- Period
- Baseline period not published by the source
- Completeness
- The source does not publish the underlying observation record.
- Method
- Interested-source claim. Heliski International has not reconstructed the measurement series.
- Limitation
- This is an operator claim for a named Valdez site, not an official normal for the entire Chugach.
- Where is the best heli-skiing in the world?Valdez Heli-Ski Guides · accessed 2026-08-25
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 |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 173.1 cm snowfall | 143.2 cm snowfall | 100.8 cm snowfall | 52.3 cm snowfall | 0 cm snowfall | 0 cm snowfall | 0 cm snowfall | 0 cm snowfall | 0 cm snowfall | 15.8 cm snowfall | 101.3 cm snowfall | 185.7 cm snowfall |
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
- Where is the best heli-skiing in the world?Valdez Heli-Ski Guides · accessed 2026-08-25
- Published operator and trip inventoryHeliski International editorial team · accessed 2026-08-25
- Global Historical Climatology Network DailyNOAA National Centers for Environmental Information · accessed 2026-08-25
- ERA5-Land monthly averaged data from 1950 to presentCopernicus Climate Change Service · accessed 2026-08-26
- Chugach Avalanche CenterChugach National Forest Avalanche Information Center · accessed 2026-08-25
- Alaska avalanche forecast centersAvalanche.org · accessed 2026-08-25
- U.S. Climate Normals 1991–2020NOAA National Centers for Environmental Information · accessed 2026-08-25