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About PTWC Messages

Message Criteria are listed by area of responsibility (message samples in parentheses).

Pacific Ocean Hawaiʻi Caribbean Sea

NOTE: Caribbean messages are unofficial at this time.

Magnitude Message Type WMO AWIPS NWW
≥7.9 Caribbean Sea-wide Tsunami Watch Message WECA41 PHEB TSUCAX HFOTSUCAX
7.6-7.8 Regional Tsunami Watch Message (sample) WECA41 PHEB TSUCAX HFOTSUCAX
7.1-7.5 Local Tsunami Watch Message WECA41 PHEB TSUCAX HFOTSUCAX
6.0-7.0 or
6.5-7.8 in
Atlantic
Tsunami Information Statement (sample) WECA43 PHEB TIBCAX HFOTIBCAX

Colors correspond to the message severity (red=most, green=least).
"WMO" = World Meteorological Organization message header (more information).
"AWIPS" = Advanced Weather Interactive Processing System header (more information).
"NWW" = NOAA Weather Wire header (more information).
For more information, see NOAAPORT.

Caribbean Sea Message Definitions:

  • Tsunami Watch
    A Tsunami Watch is issued by PTWC following a large earthquake to inform that there is the potential for a destructive tsunami to impact the region declared under a watch, or to inform regarding a confirmed tsunami with the potential to cause damage to the region declared under a watch. It is the highest level of alert issued by PTWC for the Caribbean region. It is issued by PTWC solely as advice to local governments that have the responsibility and authority to issue tsunami warnings for the areas under their jurisdiction or otherwise alert and instruct the public regarding appropriate response actions. Such actions may include the evacuation of low-lying areas and the repositioning of ships and boats to deep water. Tsunami Watch messages will be issued approximately every hour with updated information including any measurements of tsunami waves and any appropriate expansion or reduction of the region under a watch until the watch is canceled.

  • Tsunami Information
    Tsunami Information, issued by PTWC in a Tsunami Information Statement, is to inform about the occurrence of a large earthquake with little or no tsunami generating potential, either because the earthquake has insufficient size, is located too far inland to disturb the sea, is too deep within the earth to significantly displace the seafloor, or some combination of the above. In rare cases, an earthquake in this category can be accompanied by a locally destructive tsunami due to a collateral tsunamigenic phenomenon such as a landslide into the sea or an undersea slump. This product is issued solely as advice to local governments that have the responsibility and authority to alert and instruct the public regarding appropriate response actions. Supplemental tsunami information may be issued if a tsunami signal is detected on nearby gauges or if there is a significant change to the preliminary earthquake parameters.

  • Tsunami Watch Cancellation
    A Tsunami Watch Cancellation issued by PTWC indicates the end of the damaging tsunami threat. A cancellation is issued after an evaluation of sea level data confirms that a destructive tsunami will not impact the area declared under a watch, or following a destructive tsunami when sea level readings indicate that the tsunami is now below destructive levels and is subsiding in most locations that can be monitored by PTWC. A cancellation is issued by PTWC solely as advice to local governments that have the responsibility and authority to alert and instruct the public regarding appropriate response actions such as issuing an "All Clear" or returning to evacuated areas.



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