Data sources and attribution

EM Snow combines open data from the services below. We are grateful to every one of them.

Open-Meteo forecast API

Weather data by Open-Meteo.com

Licence: Data CC BY 4.0; free hosted API is non-commercial · https://open-meteo.com/

Self-hosted Open-Meteo (AWS Open Data sync)

Weather data by Open-Meteo.com

Licence: Data CC BY 4.0 (s3://openmeteo, AWS Open Data); server AGPLv3 (run stock, no modifications) · https://github.com/open-meteo/open-data

Open-Meteo AWS Open Data ERA5 mirror

ERA5 and ERA5-Land data distributed by Open-Meteo under CC BY 4.0

Licence: CC BY 4.0 · https://github.com/open-meteo/open-data

Météo-France AROME/ARPEGE model output

Météo-France, AROME and ARPEGE model data via meteo.data.gouv.fr, Licence Ouverte 2.0, forecast runs updated continuously

Licence: Licence Ouverte v2.0 (Etalab): commercial use and redistribution with attribution · https://meteo.data.gouv.fr/

ECMWF open data (IFS and AIFS)

Based on data and products of the European Centre for Medium-Range Weather Forecasts (ECMWF)

Licence: CC BY 4.0 plus ECMWF Terms of Use (attribution wording prescribed, removable on ECMWF request) · https://www.ecmwf.int/en/forecasts/datasets/open-data

Open-Meteo archive (ERA5, Copernicus CDS)

Contains modified Copernicus Climate Change Service information (ERA5)

Licence: CC BY 4.0 (CDS licence change 2025-07-02) · https://open-meteo.com/en/docs/historical-weather-api

ERA5-Land hourly data from 1950 to present (Copernicus C3S / ECMWF)

Contains modified Copernicus Climate Change Service information [2026]. Neither the European Commission nor ECMWF is responsible for any use that may be made of the Copernicus information or data it contains.

Licence: CC-BY (CDS dataset page, read 2026-09-15; dataset update date 2026-09-15). DOI 10.24381/cds.e2161bac · https://cds.climate.copernicus.eu/datasets/reanalysis-era5-land

ERA5 hourly data on single levels from 1940 to present (Copernicus C3S / ECMWF)

Contains modified Copernicus Climate Change Service information [2026]. Neither the European Commission nor ECMWF is responsible for any use that may be made of the Copernicus information or data it contains.

Licence: CC-BY (CDS dataset page). DOI 10.24381/cds.adbb2d47 · https://cds.climate.copernicus.eu/datasets/reanalysis-era5-single-levels

OpenStreetMap ski data via OpenSkiMap

Map data (c) OpenStreetMap contributors, via OpenSkiMap.org

Licence: ODbL 1.0 · https://openskimap.org/

Wikidata

Structured data from Wikidata

Licence: CC0 1.0 Universal (Public Domain Dedication) · https://www.wikidata.org/

Unicode Unihan Database

Copyright (c) 1991-present Unicode, Inc. Unihan kMandarin readings, unicode.org/copyright.html

Licence: Unicode License v3 (Data Files and Software) · https://www.unicode.org/reports/tr38/

WSL Institute SLF (CH measured snow)

WSL Institute for Snow and Avalanche Research SLF

Licence: SLF public measurement API · https://www.slf.ch/

GeoSphere Austria (AT measured snow)

GeoSphere Austria

Licence: CC BY 4.0 · https://www.geosphere.at/

Meteo-France nivo network (FR measured snow)

Météo-France réseau nivo-météorologique

Licence: Licence Ouverte 2.0 · https://meteofrance.com/

USDA NRCS SNOTEL (US measured snow)

USDA NRCS SNOTEL

Licence: US public domain · https://www.nrcs.usda.gov/

NVE seNorge/gts (NO measured snow)

NVE (seNorge/gts.nve.no)

Licence: NVE open data · https://www.nve.no/

SMHI öppna data (SE measured snow)

SMHI öppna data

Licence: CC BY 4.0 · https://www.smhi.se/

BC Automated Snow Weather Stations (CA measured snow)

BC Automated Snow Weather Stations (gov.bc.ca)

Licence: BC Open Government Licence · https://www.gov.bc.ca/

Snowy Hydro snow courses (AU measured snow)

Snowy Hydro Ltd snow courses

Licence: Snowy Hydro public data · https://www.snowyhydro.com.au/

Japan Meteorological Agency AMeDAS (JP measured snow)

Japan Meteorological Agency (AMeDAS)

Licence: JMA open data · https://www.jma.go.jp/

Agencija RS za okolje ARSO (SI measured snow)

Agencija RS za okolje (ARSO)

Licence: ARSO public data · https://www.arso.gov.si/

Czech Hydrometeorological Institute CHMI (CZ measured snow)

Czech Hydrometeorological Institute (ČHMÚ), opendata.chmi.cz

Licence: CC BY 4.0 · https://opendata.chmi.cz/

European Avalanche Warning Services (EAWS)

European Avalanche Warning Services (EAWS) member agencies

Licence: CC BY family (per-member country, see eaws.org) · https://www.avalanches.org/

Avalanche Canada

Avalanche forecast: Avalanche Canada (avalanche.ca)

Licence: Written permission from Avalanche Canada (obtained by Lee, 2026-09-27) · https://avalanche.ca/

avalanche.org

Avalanche danger from the issuing avalanche centre via avalanche.org (National Avalanche Center)

Licence: Provider terms; no open-data licence recorded · https://avalanche.org/

Windy.com webcams

Webcams provided by windy.com - add new webcam

Licence: Windy Webcams API v3 terms of use (account.windy.com/agreements/windy-api-webcams-terms-of-use) · https://www.windy.com/

Foursquare Places ratings

Ratings data via Foursquare

Licence: Foursquare Places API terms · https://location.foursquare.com/

Resort operator lift and snow feeds

Lift status courtesy of the named resort operators

Licence: Per-operator; see perFeed triage

swisstopo swissALTI3D

Source: Federal Office of Topography swisstopo

Licence: swisstopo open government data, free of charge including commercial use, source reference required · https://www.swisstopo.admin.ch/en/height-model-swissalti3d

IGN MNT LiDAR HD (France)

IGN, MNT LiDAR HD, Licence Ouverte 2.0; dataset update date recorded per clip in the DEM manifest Source dataset last updated 2025-05-01.

Licence: Licence Ouverte / Open Licence 2.0 (etalab), commercial use permitted with attribution · https://geoservices.ign.fr/lidarhd

BEV ALS DTM Austria 1 m

Digitales Gelaendemodell (DTM) Oesterreich, BEV, CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/), clipped and resampled for per-resort use Source dataset last updated 2025-09-15.

Licence: CC BY 4.0 · https://data.bev.gv.at/geonetwork/srv/api/records/9a4e3e4f-2cd5-4f73-af51-384beb9331d0

LINZ NZ LiDAR DEM

Sourced from LINZ, CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/), clipped and resampled for per-resort use Source dataset last updated 2025-06-29.

Licence: CC BY 4.0 · https://www.linz.govt.nz/products-services/data/types-linz-data/elevation-data

NSW SIX Maps Elevation (Spatial Services)

© State of New South Wales (Spatial Services, DCS), CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/), clipped and resampled for per-resort use

Licence: CC BY 4.0 · https://www.spatial.nsw.gov.au/

USGS 3DEP (The National Map)

Elevation data courtesy of the U.S. Geological Survey (3DEP / The National Map), public domain

Licence: Public Domain · https://www.usgs.gov/3d-elevation-program

CUZK DMR 5G (Czechia)

© Czech Office for Surveying, Mapping and Cadastre (CUZK), DMR 5G, CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/), clipped and resampled for per-resort use

Licence: CC BY 4.0 · https://geoportal.cuzk.cz/

Kartverket National Height Model (Norway)

© Kartverket (hoydedata.no), National Height Model (NHM DTM), Norwegian Licence for Open Government Data (NLOD 2.0), clipped and resampled for per-resort use

Licence: NLOD 2.0 / CC BY 4.0 · https://hoydedata.no/

CanElevation HRDEM (NRCan)

Contains information licensed under the Open Government Licence – Canada, © Natural Resources Canada

Licence: Open Government Licence - Canada · https://open.canada.ca/en/open-government-licence-canada

GSI Japan digital elevation model (DEM5A/DEM5B/DEM10B)

Elevation data: Geospatial Information Authority of Japan (Kokudo Chiriin), https://maps.gsi.go.jp/development/ichiran.html

Licence: GSI Content Usage Terms, base survey result (kihon sokuryo seika); real-time load via web/app requires attribution only, no application · https://www.gsi.go.jp/kikakuchousei/kikakuchousei40182.html

Copernicus DEM GLO-30

Produced using Copernicus WorldDEM-30 © DLR e.V. 2010-2014 and © Airbus Defence and Space GmbH 2014-2018 provided under COPERNICUS by the European Union and ESA; all rights reserved. The organisations in charge of the Copernicus programme by law or by delegation do not incur any liability for any use of the Copernicus WorldDEM-30

Licence: Free for any use including commercial, subject to the Copernicus DEM licence notice · https://registry.opendata.aws/copernicus-dem/

Copernicus Atmosphere Monitoring Service (CAMS), UV index

Generated using Copernicus Atmosphere Monitoring Service information; distributed via Open-Meteo self-hosted sync (CC BY 4.0 redistribution)

Licence: Copernicus free and open data policy (Regulation (EU) No 1159/2013): worldwide, royalty-free reuse including commercial, attribution required · https://atmosphere.copernicus.eu/

Global Wind Atlas 4.0

Data obtained from the Global Wind Atlas version 4.0, a free, web-based application developed, owned and operated by the Technical University of Denmark (DTU). The Global Wind Atlas version 4.0 is released in partnership with the World Bank Group, utilizing data provided by Vortex, using funding provided by the Energy Sector Management Assistance Program (ESMAP). For additional information: https://globalwindatlas.info | Citation: Davis, N.N., Badger, J., Hahmann, A.N. et al. (2023), The Global Wind Atlas: A high-resolution dataset of climatologies and associated web-based application, Bulletin of the American Meteorological Society 104(8): E1507-E1525, DOI: https://doi.org/10.1175/BAMS-D-21-0075.1

Licence: CC BY 4.0 (modified: clipped to resort areas and aggregated along lift geometry) · https://globalwindatlas.info

ESA WorldCover 10 m v200 (2021)

© ESA WorldCover project 2021 / Contains modified Copernicus Sentinel data (2021), processed by ESA WorldCover consortium

Licence: CC BY 4.0 (modified: zonal aggregation along piste corridors) · https://esa-worldcover.org

Esri World Imagery (ArcGIS Location Platform)

Imagery © Esri, Maxar, Earthstar Geographics (rendered on-map on the resortinfo sun map and /flyby satellite bases)

Licence: Esri Master Agreement via ArcGIS Location Platform keyed API (free tier: 2,000,000 basemap tiles/month, then $0.15/1k) · https://location.arcgis.com/

Sentinel-2 cloudless by EOX

Sentinel-2 cloudless 2025 by EOX (rendered on-map when active), modified Copernicus Sentinel data

Licence: CC BY-NC-SA 4.0 (EOX::Maps free tier - NON-COMMERCIAL) · https://maps.eox.at/

swisstopo SWISSIMAGE (orthophoto)

©swisstopo

Licence: swisstopo open government data, free of charge including commercial use, source reference required · https://www.swisstopo.admin.ch/en/terms-of-use-free-geodata-and-geoservices

basemap.at Orthofoto

Datenquelle: basemap.at

Licence: Open Government Data Oesterreich, CC BY 4.0 · https://basemap.at/

IGN BD ORTHO (Geoplateforme WMTS)

IGN

Licence: Licence Ouverte / Open Licence 2.0 (Etalab) · https://geoservices.ign.fr/cgu-licences

NOAA CPC Oceanic Niño Index (ONI)

NOAA Climate Prediction Center

Licence: US Government work, public domain · https://www.cpc.ncep.noaa.gov/data/indices/oni.ascii.txt

NOAA CPC North Atlantic Oscillation (NAO) index

NOAA Climate Prediction Center

Licence: US Government work, public domain · https://www.cpc.ncep.noaa.gov/products/precip/CWlink/pna/norm.nao.monthly.b5001.current.ascii.table

OpenHolidaysAPI school and public holiday database

Contains information from the OpenHolidaysAPI holiday database (https://github.com/openpotato/openholidaysapi.data), which is made available under the Open Database License (ODbL) 1.0, https://opendatacommons.org/licenses/odbl/1-0/

Licence: ODC Open Database License (ODbL) 1.0 — https://opendatacommons.org/licenses/odbl/1-0/ · https://github.com/openpotato/openholidaysapi.data

GOV.UK bank holidays (England and Wales, Scotland, Northern Ireland)

Contains public sector information licensed under the Open Government Licence v3.0

Licence: Open Government Licence v3.0 — https://www.nationalarchives.gov.uk/doc/open-government-licence/version/3/ · https://www.gov.uk/bank-holidays.json

Extreme Media curated school calendars (GB, DK, SE)

School calendars for Great Britain, Denmark and Sweden compiled by Extreme Media Snow from published government, local-authority and municipal term dates; approximate

Licence: Compiled by Extreme Media Snow from the public sources cited per country in data/crowd-curated-holidays.json · https://snow.extreme-media.co.uk/attribution

Eurostat tourism occupancy (tour_occ_nim, tour_occ_ninraw, tour_occ_nin2)

Source: Eurostat, tour_occ_nim, tour_occ_ninraw, tour_occ_nin2, data adapted by Extreme Media Snow. Eurostat is not responsible for any use made of this adaptation.

Licence: Commission Decision 2011/833/EU: reuse for commercial and non-commercial purposes authorised provided the source is acknowledged · https://ec.europa.eu/eurostat/web/main/help/copyright-notice

OnTheSnow resort reports

Resort season dates and snow reports via OnTheSnow

Licence: Proprietary, no public licence. Undocumented public JSON endpoint (api.onthesnow.com/api/v2) serving the operator of the onthesnow.com site. · https://www.onthesnow.com/

Registry version 1, updated 2026-09-26.