Sources
Where AlertWatch World gets its weather alert information
AlertWatch World brings together weather alert information from official government and meteorological sources and presents it in a common map and dashboard.
AlertWatch World does not issue weather warnings. The issuing meteorological or public authority remains the authoritative source for the warning, its instructions, and any subsequent update or cancellation.
Coverage varies by source and country. A warning may be unavailable to AlertWatch because of source availability, technical interruptions, data-format differences, or limitations in the feeds made available by an issuing authority. The absence of a displayed alert does not prove that an area is safe or that AlertWatch World has complete coverage.
On this page
U.S. National Weather Service
For the United States, AlertWatch World uses alert information from the U.S. National Weather Service (NWS).
NWS alerts are collected from the agency’s active-alert services and processed into AlertWatch’s common publication format. Where appropriate, AlertWatch may also use official NWS geographic reference information to associate an alert with its affected forecast, coastal, or marine zone.
NWS-sourced alerts are included in:
- the default Worldwide view;
- the U.S. / Canada direct-source view; and
- the NWS-only view.
The National Weather Service states that information on its web pages is generally in the public domain unless specifically noted otherwise. NWS information may be reused for lawful purposes, but reuse must not falsely claim ownership, imply NOAA/NWS endorsement or affiliation, or present modified material as official government information.
NWS disclaimer and information reuse
Source: U.S. National Weather Service / NOAA.
AlertWatch World is independent of NOAA and the National Weather Service and is not endorsed by them.
Environment and Climate Change Canada — land weather alerts
For Canadian land areas, AlertWatch World uses official weather alert information from Environment and Climate Change Canada (ECCC).
These records include warnings, watches, advisories, statements, and other alert products made available through ECCC’s weather-alert data services.
ECCC land alerts are included in:
- the default Worldwide view; and
- the U.S. / Canada direct-source view.
The Government of Canada’s Open Government Portal identifies the Weather Alerts dataset as an Environment and Climate Change Canada dataset licensed under the Open Government Licence – Canada.
Open Government Licence – Canada
The licence permits copying, modification, publication, adaptation, distribution, and commercial or non-commercial use, subject to its conditions. Those conditions include acknowledging the source and avoiding any suggestion of official status or endorsement.
Source: Environment and Climate Change Canada. Contains information licensed under the Open Government Licence – Canada.
AlertWatch World is not affiliated with or endorsed by Environment and Climate Change Canada or the Government of Canada.
Environment and Climate Change Canada — marine alerts
AlertWatch World also processes selected official Canadian marine warning information supplied through ECCC’s Marine forecasts and warnings data services.
Marine information is handled separately from Canadian land alerts because marine products differ in structure, geographic areas, timestamps, and warning characteristics.
AlertWatch publishes only marine records that pass the project’s reviewed publication checks. Ordinary marine forecasts are not treated as alerts. When a marine warning refers to a subdivision that AlertWatch cannot associate with sufficiently reliable geometry, the record may be withheld rather than displayed as though the entire parent marine area were affected.
Canadian marine warnings are included in:
- the default Worldwide view; and
- the U.S. / Canada direct-source view.
Source: Environment and Climate Change Canada / Meteorological Service of Canada.
WMO Severe Weather Information Centre
For broader international coverage, AlertWatch World uses warning information made available through the World Meteorological Organization’s Severe Weather Information Centre (WMO/SWIC).
SWIC brings together official warning information issued by participating National Meteorological and Hydrological Services and other designated meteorological centres.
The underlying warnings remain warnings of their respective issuing authorities.
AlertWatch identifies WMO/SWIC as the distribution source while preserving the available issuing-authority information associated with individual warning records.
Canada and the United States are excluded from AlertWatch’s WMO ingestion where the project’s direct ECCC and NWS pipelines provide those countries’ alerts. The default Worldwide publication combines those direct sources with the remaining WMO/SWIC international records.
WMO cautions that coverage is not universal. Warnings may be absent because an authority does not publish them in the required format, a feed is inaccessible, or a warning cannot be displayed for technical reasons. Sea-area coverage may also be incomplete.
WMO/SWIC coverage and information notes
Source: World Meteorological Organization Severe Weather Information Centre and the respective issuing meteorological or alerting authority.
OpenStreetMap
The interactive Weather map uses map tiles and geographic context provided by OpenStreetMap.
Visible OpenStreetMap attribution is maintained on the map.
OpenStreetMap’s public tile-use policy requires visible attribution and normal browser request/caching behaviour and prohibits bulk downloading or offline prefetching from the public tile service.
OpenStreetMap copyright and attribution
© OpenStreetMap contributors.
Leaflet
AlertWatch World’s interactive map is built with Leaflet, an open-source JavaScript mapping library.
Leaflet is distributed under the BSD 2-Clause licence. AlertWatch retains Leaflet attribution on the interactive map and acknowledges the library here.
Leaflet 1.9.4 BSD 2-Clause licence
What “Worldwide” means
“Worldwide” does not mean that AlertWatch World has complete warning coverage for every country, territory, marine area, or hazard.
It means that the Worldwide publication combines:
- direct NWS alert information for the United States;
- direct ECCC land and marine alert information for Canada; and
- available international warning records supplied through WMO/SWIC.
Participation, warning formats, geographic information, language, update practices, and feed availability differ among issuing authorities.
A country with no records displayed on AlertWatch World may still have an alert that is unavailable through the sources AlertWatch currently processes.
Source information and AlertWatch processing
AlertWatch does not simply reproduce every incoming field unchanged.
Different source systems describe warning severity, geography, timestamps, event names, lifecycle state, and instructions differently. AlertWatch normalizes selected fields into a common structure so that records from multiple sources can be displayed through one interface.
Those transformations are described on the Methodology page.
Where AlertWatch modifies presentation, groups records, resolves geometry, or assigns a common display category, those changes are AlertWatch processing and should not be interpreted as changes made by the original issuing authority.
Official information comes first
AlertWatch World is intended to make official alert information easier to discover and understand.
For urgent decisions, always follow information and instructions from the applicable official meteorological service, emergency-management authority, local government, or other responsible authority.
AlertWatch World is not an emergency service and does not issue warnings.
Source availability and corrections
Official feeds can change, become temporarily unavailable, contain incomplete fields, or publish information that AlertWatch cannot safely normalize or display.
AlertWatch uses validation and fallback procedures intended to reduce publication errors, but those checks do not independently confirm weather conditions or events on the ground.
When AlertWatch identifies a source or processing problem, the project may correct, withhold, regroup, or update displayed records while preserving the distinction between AlertWatch’s presentation and the original issuing authority’s information.