Tsunami Watches and Warnings, what they mean to you.
Tsunami Warning: Indicates that a tsunami is
imminent and that coastal locations in the warned area should prepare for
flooding. A bulletin, initially based only on seismic information without
tsunami confirmation, issued as a means of providing the earliest possible
alert to at-risk populations. Warnings initially place a restricted area in a
condition that requires all coastal areas in the region to be prepared for
imminent flooding. The tsunami warning will cover an area within a 3-hour
tsunami wave travel time from the time of bulletin issuance. Subsequent bulletins are issued at least hourly or as
conditions warrant to continue, expand, restrict, or end the warning. In the event a tsunami has been confirmed
which could cause damage outside the source region, the warning will be
extended as appropriate.
For an example CLICK HERE.
Tsunami Watch: An alert issued to
areas outside the warned area. A
bulletin, usually based only on seismic information without tsunami
confirmation, issued as a means of alerting the population within 1 to 3 hours
tsunami travel time beyond the tsunami warning area of an earthquake with the
potential to have generated a tsunami that may affect the watch area. The tsunami watch will be issued for areas within the 3- to 6-hour tsunami wave travel time.Subsequent bulletins are issued at least hourly or as conditions warrant to
expand the watch area, upgrade it to a warning, or cancel the watch and
warning. A Tsunami Watch is normally included in the text of the message that
disseminates a Tsunami Warning.
For an example CLICK HERE.
Tsunami Advisory: A message
issued when the Pacific
Tsunami Warning
Center has issued a
warning for an event outside the WC/ATWC AOR (area of responsibility) which poses no imminent threat to
the AOR. A bulletin
issued to areas not currently in either warning or watch status when a tsunami
warning has been issued for another region of an ocean. An Advisory indicates
that an area is either outside the current warning and watch regions, or that
the tsunami poses no danger to that area. The WC/ATWC will continue to monitor
the event, issuing updates at least hourly. As conditions warrant, the Advisory
will either be continued, upgraded to a watch or warning, or ended.
For an example CLICK HERE.
Tsunami Information
Bulletin: Informational bulletins issued for earthquakes which
are not likely to trigger a tsunami dangerous to the AOR. A bulletin
issued to advise participants of the occurrence of an earthquake with the
evaluation that a potentially destructive tsunami was not generated, or that an
earthquake has occurred outside the TWCs AOR and could potentially generate a
tsunami. If the evaluation indicates the possible generation of a destructive
or nondestructive tsunami, an investigation will be initiated and additional
tsunami information bulletins will be issued as warranted until the investigation
is concluded.
For an example CLICK HERE.
Tsunami
Information Message: Information messages
issued when smaller earthquakes (less than the warning threshold) may be felt
near coastal areas. These messages are
issued to assure coastal residents and emergency managers that there is no
tsunami danger.
For an example CLICK HERE.
*How long does it take for a tsunami to reach the coast of Southwest Oregon? Click HERE to see a map of travel times.
*For general information on Tsunamis, click HERE.
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