West Coast and Alaska Tsunami Warning Center

Frequently Asked Questions

What do the various icons on the map mean ?

Icon	Meaning
	Earthquake Icon - Identifies the location of the seismic event.
	Warning Icon - Indicates a tsunami warning. This means an inundating wave possible and full evacuation is suggested.
	Advisory Icon - Indicates a tsunami advisory. This means strong currents are likely. Stay away from the shore.
	Watch Icon - Indicates a tsunami watch. This means the danger level is not yet known. Stay alert for more info.
	Info Icon - Indicates minor waves at most and that no actions are currently suggested.
	Link Icon - Indicates more information can be obtained by clicking on the map marker.
	Dart icon/marker - Indicates the location of a Dart Buoy (see the 'What is a Dart Buoy' question).
	Previous event icon/marker - Indicates the location of a previous seismic event.
	Tide gauge icon/marker - Indicates the location of a tide gauge.
	Tide gauge icon/marker - Indicates the location of Break Point.
	Previous event icon/marker - Indicates the location of previous significant seismic event.

Click for more details regarding tsunami Watch/Warning/Advisory

What is a Dart Buoy ?

Deep-ocean Assessment and Reporting of Tsunamis (DART) is a real-time tsunami monitoring system. Dart Buoy's are located at strategic locations throught the ocean.

More information can be located at:

Pacific Marine Environmental Laboratory
National Data Buoy Center
National Data Buoy Center Dart Page

On the main map, when you move the mouse to click on the bulletin, the pop up disappears - Why ?

To view the bulletin, just click your mouse without moving it.
If you move your mouse, then the pop up automatically closes. This is to prevent potentially hundreds of pop up dialog boxes remaining open (i.e., potentially hundreds of dialog boxes that would need to be closed).

What does the travel time map tell me?

The travel time map shows expected travel time (in hours) from a seismic event anywhere in an ocean basin to coastal locations. Contours on the map represent one hour intervals. Each change in color shade of a contour line is a one hour mark (see graphic below).

N.B. Due to source uplift size in an actual event, travel times shown on the map may be in error up to 30 minutes.

travel time graphic

What does the energy map signify ?

Contours of forecasted maximum wave amplitudes (in centimeters), detailing the tsunami energy propagation. The scale on the right hand side of the graphic maps the color to the height.

energy map graphic

What does the observations and forecast page show me ?

The observations and forecast page shows both predicted wave heights (in feet) - based of the results of a modeling program. The observations are the actual reported wave heights as observered (in feet).

N.B. Any value greater than 0.3 meters and less than 1.0 meters is marked in orange (Advisory), while any value greater than, or equal to 1.0 meters is marked in red (Warning).

screen shot of forecast page

How accurate is the map overlay for a Watch/Warning/Advisory ?

When a Watch/Warning/Advisory overlay is depicted on the map - this allows you (at a high level) to see what stretches of coastal area are in a Watch/Warning/Advisory. Google maps allows you to zoom in and view the coastal area at a low level. Inland cities may be colored as being in a Watch/Warning/Advisory - but that does NOT mean they are actually in a Watch/Warning/Advisory. If in doubt, please check with your local Emergency Managers, Weather Forecast Office, or Police.

The overlays are actually the NWS coastal Zone colored to match a Watch/Warning/Advisory (see: http://www.nws.noaa.gov/mirs/public/prods/maps/pfzones_list.htm. So the entire NWS coastal zone is colored rather than specific innundation zones.

screen shot of Watch/Warning/Advisory Overlay

screen shot of Watch/Warning/Advisory Overlay

If you have a question/comment we would love to hear from you.