Identify the Canadian coastline and authority
Canada has more than one coastline. This guide concerns British Columbia's Pacific coast and the provincial information used there; it does not apply BC zones to Atlantic or Arctic communities. The province's PreparedBC tsunami information explains its coastal notification zones and official information channels. Begin with the locality and the responsible authority, not just the word Canada in a map title.
The BC notification-zone dataset provides geographic context for those notification areas. These boundaries support communication about coastal areas. They are not a street-by-street prediction of flood depth, an evacuation route or a guarantee that every place inside a coloured zone has the same exposure.
Read the provincial message with the source bulletin
EmergencyInfoBC publishes verified provincial emergency information. For a particular event, keep the current provincial message, affected notification zones and update time together. When it links to an international or US warning-centre bulletin, compare the latest versions of both rather than treating the two pages as permanently identical copies.
The US Tsunami Warning Centers map includes US and Canadian coastal messages. Its earthquake markers, monitoring locations and alert layers are different information types. An earthquake location does not by itself tell a Canadian community which provincial notice applies. Conversely, a selected BC zone does not turn every monitoring symbol inside it into an observed tsunami.
A useful way to document a BC comparison
Keep the notification-zone legend with any exported image. A zone letter without its official geographic description is not sufficient context for a reader elsewhere.
For research or a news explanation, name the coastal community, identify its notification area using the official zone information and link the current provincial notice. Then record the warning-centre bulletin's issue time and message type. If one page is newer, state that difference instead of combining fragments from different updates into an invented current summary. Preserve any time-zone label shown by the source.
The PocketWorld tsunami explorer helps locate available event records in their wider ocean context. It does not provide a complete BC notification or inundation layer and is not an emergency alert service. Missing global records do not invalidate local instructions. An archived alert, a historical zone map and a current bulletin can all be legitimate documents with different purposes. Keeping those purposes visible is more useful than searching for one supposedly definitive colour on a global map. For immediate decisions, follow local emergency instructions and official warning channels; do not use this explanatory page as a substitute or delay action while comparing viewers.
Data sources
References are linked beside the explanations above. This evergreen guide does not report current incidents.