Evidence and governance

How we publish mountain intelligence.

The method favours an explicit gap over a precise-looking number that cannot represent the terrain.

No proprietary safety score

We do not calculate safety, powder, flyability, or avalanche scores.

Structured provenance

Values require source, site, elevation when available, period, method, confidence, and caveat.

Original links

Current public bulletins remain on the official publisher and keep their issue and validity context.

Comparable meaning

Snowfall, depth, snow-water equivalent, and operator marketing totals remain separate measures.

Source hierarchy

Use the strongest representative evidence available.

  1. A

    Official 1991–2020 climate normal

    A published standard normal from a geographically and elevationally relevant site.

  2. B

    Named observed reference series

    Quality-controlled station or snow-network observations with period and completeness.

  3. C

    Calibrated gridded or reanalysis estimate

    A model product calibrated and cross-validated against regional observations.

  4. D

    Satellite snow-cover evidence

    Observed cover timing or persistence. It never becomes a snowfall amount.

  5. E

    Commercial claim

    Useful local context, clearly marked as an interested source with low confidence.

  6. F

    Insufficient representative evidence

    A precise documented gap with no numeric estimate.

Display contract

What every material claim must carry.

  • Publisher and direct source URL
  • Measurement site and elevation when available
  • Normal or observation period
  • Method and transformation
  • Confidence and representativeness caveat
  • Review date, rights note, and correction path

Geographic contract

A gateway is not a measurement area.

  • Each profile names its documented reference area and catalogue-linked locations.
  • Operating tenures remain separate unless a public, reusable boundary exists.
  • Reference sites retain published coordinates and distances when available. Unavailable values stay explicit.
  • Overlapping Alaska, Iceland, British Columbia, and New Zealand profiles have explicit exclusions.
  • A broad destination centroid never creates a mountain estimate.
  • Unknown terrain elevation bands remain visible instead of being inferred.

Reproducibility

Dataset 2026.08.25.1

  • NOAA snowfall uses quality-flagged daily values and July–June snow years.
  • Canadian SWE uses each October–September season maximum and excludes seasons with fewer than two observations.
  • SMHI snow depth uses quality-controlled daily values and excludes incomplete snow years.
  • Published New Zealand summaries retain their reported mean, range, record length, and short-series limitation.
  • Missing years never become zeros.
  • Source rights and access dates remain in the public registry.

Source registry

46 reviewed records.

Links were checked on 25 August 2026. The external publisher controls availability and terms.

editorial inventory

  • Published operator and trip inventory

    Heliski International editorial team

    Typical operating windows checked against the current operator and trip catalogue.Heliski International editorial record.

standard

  • WMO Climatological Normals

    World Meteorological Organization

    Global climate-normal definitions and the 1991–2020 reference period.Link only. The publisher retains all content and data rights.
  • European Avalanche Danger Scale

    European Avalanche Warning Services

    European five-level danger scale, definitions, and travel advice.Link only. The publisher retains all content and data rights.
  • Avalanche Problems

    European Avalanche Warning Services

    Standard avalanche-problem definitions and their typical duration and distribution.Link only. The publisher retains all content and data rights.
  • North American Public Avalanche Danger Scale

    Avalanche.org and the U.S. Forest Service National Avalanche Center

    North American five-level danger scale and its limitations.Link only. The publisher retains all content and data rights.

official climate

  • ERA5-Land hourly data from 1950 to present

    Copernicus Climate Change Service

    Global gridded reanalysis used only when station evidence is insufficient.Copernicus licence and attribution terms apply.
  • Historical Climate Data

    Environment and Climate Change Canada

    Canadian station observations and climate normals.Government of Canada terms apply.
  • U.S. Climate Normals 1991–2020

    NOAA National Centers for Environmental Information

    United States station temperature, precipitation, snowfall, and snow-depth normals.United States Government data terms apply.
  • Antarctic meteorology and data

    British Antarctic Survey

    Antarctic environmental observations and research data; not an operational avalanche bulletin.British Antarctic Survey data terms apply.

satellite

official weather

  • World Weather Information Service

    World Meteorological Organization

    Official forecasts and climatological information supplied by national services.Link only. The publisher retains all content and data rights.
  • MeteoUYARI warning map

    Turkish State Meteorological Service

    Two-day severe-weather warning map that can include avalanche warnings.Link only. The publisher retains all content and data rights.
  • National Environmental Agency weather and warnings

    National Environmental Agency of Georgia

    National weather forecasts and warnings; no verified public regional avalanche bulletin was identified.Link only. The publisher retains all content and data rights.
  • Weather and warnings

    Kazhydromet

    Kazakhstan national forecasts and severe-weather warnings.Link only. The publisher retains all content and data rights.
  • Weather and hazard information

    KyrgyzHydromet

    Kyrgyz Republic weather forecasts and hazard information.Link only. The publisher retains all content and data rights.
  • Hydrometeorological Centre of Russia

    Roshydromet

    Russian national weather forecasts and warnings.Link only. The publisher retains all content and data rights.
  • Mountain weather and warnings

    Romanian National Meteorological Administration

    Romanian forecasts and warnings, including seasonal mountain information.Link only. The publisher retains all content and data rights.
  • Forecasts and meteorological warnings

    Dirección Meteorológica de Chile

    Chilean forecasts and warnings for Central and Southern Andes planning.Link only. The publisher retains all content and data rights.
  • Forecasts and early warnings

    Servicio Meteorológico Nacional Argentina

    Argentine national forecasts and early-warning products.Link only. The publisher retains all content and data rights.
  • Greenland weather

    Danish Meteorological Institute

    Official Greenland forecasts and observations.Link only. The publisher retains all content and data rights.

official snow

  • Global Historical Climatology Network Daily

    NOAA National Centers for Environmental Information

    Quality-flagged daily snowfall and snow-depth station observations with fixed-format metadata.United States Government data terms apply.
  • Canadian Historical Snow Survey Data

    Environment and Climate Change Canada

    Canadian snow-course and snow-pillow observations, including snow depth and snow-water equivalent.Open Government Licence – Canada applies. Some restricted provincial records are excluded.
  • Quality-controlled daily snow depth at Abisko

    Swedish Meteorological and Hydrological Institute

    Daily snow-depth observations at 06:00 UTC for SMHI station 188800, Abisko.CC0 1.0 applies to SMHI open data.
  • Winter snowfall summary from high-elevation stations

    Earth Sciences New Zealand

    Published winter snowfall averages, observed ranges, elevations, and record lengths for high-elevation stations.Link only. The publisher retains all content and data rights.

official avalanche

  • Avalanche Canada forecast map

    Avalanche Canada

    Public regional forecasts across most mountain regions in western Canada.Link only. The publisher retains all content and data rights.
  • Chugach Avalanche Center

    Chugach National Forest Avalanche Information Center

    Seasonal public forecasts for Turnagain Pass and adjacent forecast zones.Link only. The publisher retains all content and data rights.
  • Alaska avalanche forecast centers

    Avalanche.org

    Directory of staffed Alaska forecast regions; substantial terrain remains uncovered.Link only. The publisher retains all content and data rights.
  • Utah Avalanche Center forecasts

    Utah Avalanche Center and U.S. Forest Service

    Public Salt Lake and other Utah regional forecasts.Link only. The publisher retains all content and data rights.
  • Sawtooth Avalanche Center

    Sawtooth Avalanche Center

    Public forecasts, observations, and weather for the Sawtooth region.Link only. The publisher retains all content and data rights.
  • Regional avalanche forecast

    Icelandic Meteorological Office

    Seasonal regional forecasts for five Icelandic areas.Link only. The publisher retains all content and data rights.
  • Avalanche Information Sweden

    Swedish Environmental Protection Agency

    National service including the Abisko and Riksgränsen forecast region.Link only. The publisher retains all content and data rights.
  • Centre de Lauegi

    Conselh Generau d’Aran

    Daily Val d’Aran avalanche bulletin, weather, stations, and observations.Link only. The publisher retains all content and data rights.
  • New Zealand Avalanche Advisory

    New Zealand Mountain Safety Council

    Public backcountry forecasts for New Zealand alpine regions.Link only. The publisher retains all content and data rights.
  • Avalanche Warning Bulletin archive

    Defence Geoinformatics Research Establishment, Government of India

    Seasonal district-level bulletins for Jammu and Kashmir, Himachal Pradesh, and other Himalayan areas.Government of India terms apply.

public safety

  • Essential avalanche rescue gear

    Avalanche Canada

    Transceiver, shovel, probe, training, and companion-rescue guidance.Link only. The publisher retains all content and data rights.
  • What is the New Zealand Avalanche Advisory?

    New Zealand Mountain Safety Council

    States that public forecasts are not for commercial heli-ski operators.Link only. The publisher retains all content and data rights.

operator claim

  • 2026 Last Frontier Heliskiing price list

    Last Frontier Heliskiing

    Operator claim of 20–30 metres of annual snowfall in its Northern British Columbia tenure.Link only. The publisher retains all content and data rights.
  • Top reasons to heli-ski in British Columbia

    Northern Escape Heli Skiing

    Operator claim of 12–15 metres annual snowfall in the Pacific coastal mountains near Terrace.Link only. The publisher retains all content and data rights.
  • Snowbird facts and frequently asked questions

    Snowbird

    Resort claim of 500 inches average annual snowfall at Snowbird.Link only. The publisher retains all content and data rights.
  • Sun Valley mountain facts

    Sun Valley Resort

    Resort marketing statistic of 200 inches annual snowfall; the measurement site is unspecified.Link only. The publisher retains all content and data rights.
  • Heli-skiing programs in Iceland

    Arctic Heli Skiing

    Operator-published Iceland and Troll Peninsula season from February through June.Link only. The publisher retains all content and data rights.
  • Val d’Aran heliski season FAQ

    Guide Val d’Aran

    Local guide statement that the season can run from early December through late April.Link only. The publisher retains all content and data rights.
  • Mount Cook Heliski operating dates

    Mount Cook Heliski

    Operator-published flying window from July through September on fine-weather days.Link only. The publisher retains all content and data rights.
  • Heliskiing season in Greenland

    Air Greenland

    Travel-provider statement that the Greenland season runs from March to early June.Link only. The publisher retains all content and data rights.
  • Heliski Patagonia program

    Andes Heliboarding

    Operator-published November window for its Patagonia heli-ski program.Link only. The publisher retains all content and data rights.
  • Where is the best heli-skiing in the world?

    Valdez Heli-Ski Guides

    Operator claim of more than 500 inches annual snowfall at Thompson Pass.Link only. The publisher retains all content and data rights.

Revision policy

Corrections remain visible in version history.

We review profiles when a source changes, a destination changes, or credible evidence challenges a claim. Contact us with the source URL, site, period, and proposed correction.

Contact the editorial team Open correction record

Review status

Editorial review is complete. External review is pending.

Editorial owner: Heliski International editorial team. Next annual review: 2027-08-25.

Open professional and accessibility review record

Open review gates

  • Meteorology

    Pending named external review in GitHub issue #229

  • Avalanche

    Pending named external review in GitHub issue #229

  • Accessibility

    Pending final manual review record in GitHub issue #229

Revision record

  • 2026.08.25.1

    2026-08-25

    Added 34 documented reference zones, evidence tiers, reproducible observed snow summaries, precise monthly gaps, and operator submission governance.
  • 2026.08.25.0

    2026-08-25

    Published the first 34 destination profiles, source registry, snow and weather guide, avalanche guide, and explicit annual snowfall gaps.

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