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.

Evidence reviewed 2026-08-26

Typical operating window

December–AprilPacific storms usually establish the operational base during late autumn and early winter.

Strongest comparable snow evidence

1,325 mm SWE median · 1,110–1,440 mm interquartile rangeTsai Creek PillowTier B · observed reference · low confidence

Snow character

maritimeFrequent maritime snowfall builds a deep base. Colder inland flow can lower surface-snow density between storms.

Public avalanche information

Avalanche Canada regional forecast mapForecast coverage depends on the exact tenure. A public region never replaces the operator assessment.

Weather and flight context

Moist Pacific systems meet the Coast and Skeena ranges, producing strong elevation and windward-leeward contrasts.

  • Embedded cloud and low ceiling
  • Heavy snowfall rates
  • Ridge wind and flat light

Meteorological reference area

Northern Coast and Skeena catalogue locations

Includes
Northern Coast and Skeena mountain evidence near published trips.
Excludes
Interior, eastern, and Bella Coola destination profiles.
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 BPeak seasonal snow-water equivalent reference1,325 mm SWE median · 1,110–1,440 mm interquartile range
Site
Tsai Creek Pillow · 54.6500, -127.6667 · 1360 m · 46 km from the catalogue reference
Period
1998/99–2010/11 complete snow seasons within the 1991–2016 archive
Completeness
13 seasons with at least two valid observations; 2,313 observations used.
Method
Maximum SWE by October–September snow season; median and quartiles across valid seasons.
Limitation
This site is one mountain reference, not a tenure-wide snowfall or snow-depth value.
Tier CModelled snowfall water equivalent953 mm SWE median · 834–1,160 mm interquartile range
Site
Skeena gateway area ERA5-Land grid cell · 54.7000, -128.4000 · 4.5 km from Skeena gateway 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.
Tier EPublished commercial snowfall claim20–30 m operator claim
Site
Last Frontier tenure in the Northern Coast and Skeena mountains
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 a tenure-wide marketing claim, not an official station normal or a promise for any run.

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.

Modelled snowfall water equivalent
JanFebMarAprMayJunJulAugSepOctNovDec
188.9 mm SWE121.3 mm SWE127.4 mm SWE72.5 mm SWE12.5 mm SWE0.5 mm SWE0 mm SWE0 mm SWE2.4 mm SWE80.2 mm SWE179.3 mm SWE171.4 mm SWE

Commercial operator assessment

Operator assessment process not independently verified

The operator must assess current snow, avalanche terrain, weather, aircraft limits, and rescue options. No private operational plan is inferred.

Sources and evidence notes

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