[nws-changes] 20070111: Tsunami warning watch advisories: ADMIN NOTICE NOUS41 KWBC]

[Linda Miller]

-------- Original Message --------

709 
NOUS41 KWBC 111812
PNSWSH

SERVICE CHANGE NOTICE 07-51...CORRECTED
NATIONAL WEATHER SERVICE HEADQUARTERS WASHINGTON DC  
212 PM EDT THU OCT 11 2007   
 
TO:       FAMILY OF SERVICES /FOS/ SUBSCRIBERS...NOAA WEATHER    
          WIRE SERVICE /NWWS/ SUBSCRIBERS...EMERGENCY MANAGERS
          WEATHER INFORMATION NETWORK /EMWIN/ SUBSCRIBERS...      
          NOAAPORT SUBSCRIBERS...OTHER NATIONAL WEATHER SERVICE   
          /NWS/ PARTNERS AND OTHER USERS...NWS EMPLOYEES  
 
FROM:     THERESE Z. PIERCE                                 
          CHIEF...MARINE AND COASTAL SERVICES BRANCH 
 
SUBJECT:  CORRECTED: CHANGE TO TSUNAMI WARNING...WATCH...ADVISORY AND 
          INFORMATION STATEMENT DEFINITIONS FOR PRODUCTS ISSUED
          BY THE WEST COAST/ALASKA TSUNAMI WARNING  
          CENTER: EFFECTIVE FEBRUARY 12 2008 

CORRECTED TO REPEAT EFFECTIVE DATE OF FEBRUARY 12 2008 IN 
PARAGRAPH DISCUSSING TABLE 1.

EFFECTIVE TUESDAY FEBRUARY 12 2008 AT 1800 COORDINATED UNIVERSAL 
TIME...THE DEFINITIONS USED FOR TSUNAMI PRODUCTS ISSUED BY THE 
WEST COAST/ALASKA TSUNAMI WARNING CENTER /WC/ATWC/ WILL BE 
REVISED TO PROVIDE BETTER INDICATION OF EXPECTED TSUNAMI IMPACT 
LEVEL AND TO MORE CLOSELY ALIGN TSUNAMI PRODUCTS TO OTHER 
NATIONAL WEATHER SERVICE /NWS/ WARNING/WATCH/ADVISORY PRODUCT 
SUITES.

THE MOST SIGNIFICANT REVISION IS TO THE TSUNAMI ADVISORY 
DEFINITION. THE NEW ADVISORY STATES A TSUNAMI IS EXPECTED THAT 
COULD BE DANGEROUS TO THOSE IN OR NEAR THE WATER...BUT NO 
SIGNIFICANT INUNDATION IS EXPECTED. CURRENTLY A TSUNAMI ADVISORY 
STATES A WATCH OR WARNING IS IN EFFECT FOR ANOTHER PART OF THE 
OCEAN BASIN...AND IT HAS NO RELATION TO POTENTIAL DANGER LEVEL.

IN SITUATIONS WHERE A TSUNAMI WARNING...WATCH OR ADVISORY IS 
ISSUED FOR ANOTHER AREA OF THE OCEAN AND THERE IS NO DANGER 
WITHIN THE WC/ATWC AREA OF RESPONSIBITY...TSUNAMI INFORMATION 
STATEMENTS WILL BE ISSUED BY WC/ATWC.

THE REVISED TSUNAMI WARNING...WATCH...ADVISORY AND INFORMATION 
STATEMENT DEFINITIONS ARE LOCATED IN TABLE 1.

TABLE 1. REVISED TSUNAMI WARNING...ADVISORY...WATCH AND 
INFORMATION STATEMENT DEFINITIONS EFFECTIVE TUESDAY FEBRUARY 12 2008.

TSUNAMI WARNING: A TSUNAMI WARNING IS ISSUED WHEN A POTENTIAL 
TSUNAMI WITH SIGNIFICANT WIDESPREAD INUNDATION IS IMMINENT OR 
EXPECTED. WARNINGS ALERT THE PUBLIC THAT WIDESPREAD... DANGEROUS 
COASTAL FLOODING ACCOMPANIED BY POWERFUL CURRENTS IS POSSIBLE AND 
MAY CONTINUE FOR SEVERAL HOURS AFTER ARRIVAL OF THE INITIAL 
WAVE. WARNINGS ALSO ALERT EMERGENCY MANAGEMENT OFFICIALS TO TAKE 
ACTION FOR THE ENTIRE TSUNAMI HAZARD ZONE. APPROPRIATE ACTIONS TO 
BE TAKEN BY LOCAL OFFICIALS MAY INCLUDE THE EVACUATION OF LOW-
LYING COASTAL AREAS AND REPOSITIONING SHIPS TO DEEP WATERS WHEN 
THERE IS TIME TO SAFELY DO SO.  WARNINGS MAY BE UPDATED... 
ADJUSTED GEOGRAPHICALLY...DOWNGRADED...OR CANCELED. TO PROVIDE 
THE EARLIEST POSSIBLE ALERT...INITIAL WARNINGS ARE NORMALLY BASED 
ONLY ON SEISMIC INFORMATION.

TSUNAMI WATCH: A TSUNAMI WATCH IS ISSUED TO ALERT EMERGENCY 
MANAGEMENT OFFICIALS AND THE PUBLIC OF AN EVENT THAT MAY LATER 
IMPACT THE WATCH AREA. THE WATCH AREA MAY BE UPGRADED TO A 
WARNING OR ADVISORY - OR CANCELED - BASED ON UPDATED INFORMATION 
AND ANALYSIS. THEREFORE EMERGENCY MANAGEMENT OFFICIALS AND THE 
PUBLIC SHOULD PREPARE TO TAKE ACTION. WATCHES ARE NORMALLY 
ISSUED BASED ON SEISMIC INFORMATION WITHOUT CONFIRMATION THAT A 
DESTRUCTIVE TSUNAMI IS UNDERWAY.

TSUNAMI ADVISORY: A TSUNAMI ADVISORY IS ISSUED FOR THE THREAT OF 
A POTENTIAL TSUNAMI THAT MAY PRODUCE STRONG CURRENTS OR WAVES 
DANGEROUS TO THOSE IN OR NEAR THE WATER. COASTAL REGIONS 
HISTORICALLY PRONE TO DAMAGE DUE TO STRONG CURRENTS INDUCED BY 
TSUNAMIS ARE AT THE GREATEST RISK. THE THREAT MAY CONTINUE FOR 
SEVERAL HOURS AFTER THE ARRIVAL OF THE INITIAL WAVE... BUT 
SIGNIFICANT WIDESPREAD INUNDATION IS NOT EXPECTED FOR AREAS UNDER 
AN ADVISORY. APPROPRIATE ACTIONS TO BE TAKEN BY LOCAL OFFICIALS 
MAY INCLUDE CLOSING BEACHES... EVACUATING HARBORS AND MARINAS... 
AND REPOSITIONING SHIPS TO DEEP WATERS WHEN THERE IS TIME TO 
SAFELY DO SO. ADVISORIES ARE NORMALLY UPDATED TO CONTINUE THE 
ADVISORY... EXPAND/CONTRACT AFFECTED AREAS... UPGRADE TO A 
WARNING... OR CANCEL THE ADVISORY.

TSUNAMI INFORMATION STATEMENT: A TSUNAMI INFORMATION STATEMENT IS 
ISSUED TO INFORM EMERGENCY MANAGEMENT OFFICIALS AND THE PUBLIC 
THAT AN EARTHQUAKE HAS OCCURRED... OR THAT A TSUNAMI WARNING... 
WATCH OR ADVISORY HAS BEEN ISSUED FOR ANOTHER SECTION OF THE 
OCEAN. IN MOST CASES INFORMATION STATEMENTS ARE ISSUED TO 
INDICATE THERE IS NO THREAT OF A DESTRUCTIVE TSUNAMI AND TO 
PREVENT UNNECESSARY EVACUATIONS BECAUSE THE EARTHQUAKE MAY HAVE 
BEEN FELT IN COASTAL AREAS. AN INFORMATION STATEMENT MAY...IN 
APPROPRIATE SITUATIONS...CAUTION ABOUT THE POSSIBILITY OF 
DESTRUCTIVE LOCAL TSUNAMIS. INFORMATION STATEMENTS MAY BE  
REISSUED WITH ADDITIONAL INFORMATION...THOUGH NORMALLY THESE 
MESSAGES ARE NOT UPDATED.  HOWEVER...A WATCH...ADVISORY OR 
WARNING MAY BE ISSUED FOR THE AREA...IF NECESSARY...AFTER 
ANALYSIS AND/OR UPDATED INFORMATION BECOMES AVAILABLE.

THE RELATIONSHIPS AMONG PRODUCT TYPE LINES AND PRODUCT 
COMMUNICATIONS IDENTIFIERS REMAIN THE SAME. 

FURTHER INFORMATION ABOUT TSUNAMI PRODUCTS AND SERVICES PROVIDED 
BY THE WC/ATWC CAN BE FOUND ONLINE AT /USE LOWER CASE LETTERS/: 

       HTTP://WCATWC.ARH.NOAA.GOV

IF YOU HAVE QUESTIONS...PLEASE CONTACT: 
 
PAUL WHITMORE   
WEST COAST AND ALASKA TSUNAMI WARNING CENTER 
NATIONAL WEATHER SERVICE 
910 SOUTH FELTON STREET 
PALMER AK 99645  
PHONE 907-745-4212
EMAIL: PAUL.WHITMORE at NOAA.GOV 

THIS NOTICE AND OTHER SERVICE CHANGE NOTICES ARE AVAILABLE ONLINE 
AT /USE LOWER CASE LETTERS/:  
 
HTTP://WWW.NWS.NOAA.GOV/OM/NOTIF.HTM

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