Author Topic: Wave Height estimates  (Read 2069 times)

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Offline Scalphunter

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Wave Height estimates
« on: February 27, 2010, 01:43:36 PM »
To: U.S. West Coast, Alaska, and British Columbia coastal regions
From: NOAA/NWS/West Coast and Alaska Tsunami Warning Center
Subject: Tsunami Advisory #11 issued 02/27/2010 at 9:04AM PST

A Tsunami Advisory is in effect which includes the coastal areas of California, Oregon, Washington, British Columbia and Alaska from the California-Mexico border to Attu, Alaska.

A Tsunami Advisory means that a tsunami capable of producing strong currents or waves dangerous to persons in or very near the water is imminent or expected. Significant, widespread inundation is not expected for areas under an advisory. Currents may be hazardous to swimmers, boats, and coastal structures and may continue for several hours after the initial wave arrival.

At 10:34 PM Pacific Standard Time on February 26, an earthquake with preliminary magnitude 8.8 occurred near the coast of central Chile . (Refer to the United States Geological Survey for official earthquake parameters.) This earthquake has generated a tsunami which could cause damage to coastal regions in a warning or advisory. The waves are expected to first reach La Jolla, California at 0:02 PM PST on February 27. Estimated tsunami arrival times and maps along with safety rules and other information can be found on the WCATWC web site.

A tsunami has been observed at the following sites:

 Location                   Lat.   Lon.    Time        Amplitude ------------------------  -----  ------  -------     -----------
 Iquique  Chile            20.2S   70.2W  0851UTC     0.30M/1.0ft
 Antofagasta  Chile        23.3S   70.4W  0956UTC     0.46M/1.4ft
 Ancud  Chile              41.9S   74.3W  0943UTC     0.34M/1.1ft
 Corral  Chile             39.9S   73.4W  1012UTC     1.54M/5.2ft
 Callao La Punta  Peru     12.1S   77.2W  1029UTC     0.66M/2.2ft
 Baltra  Ecuador            0.4S   90.3W  1430UTC     0.45M/1.5ft
 Quepo  Costa Rica          9.4N   84.2W  1417UTC     0.27M/0.9ft
 Acapulco  Mexico          16.8N   99.9W  1549UTC     0.34M/1.1ft
 Santa Cruz  Galapagos E    0.5S   90.2W  1241UTC     1.07M/3.5ft
 Manzanillo  Mexico        19.0N  104.2W  1636UTC     0.23M/0.7ft
 Tsunami Forecasts at selected points -
 La Jolla, CA     0.8M/2.6 FT    Los Angeles, CA  0.8M/2.6 FT
 Mailbu, CA       1.0M/3.3 FT    Pismo Beach, CA  1.4M/4.6 FT
 Half Moon Bay, CA 1.0M/3.3 FT   San Francisco, CA 0.2M/0.7 FT
 Humboldt Bay, CA  0.4M/1.3FT    Crescent City, CA 0.6M/2.0 FT
 Port Orford, OR   0.3M/1.0 FT   Moclips, WA      0.4M/1.3 FT
 Tofino, BC        0.5M/1.7 FT   Sitka, AK        0.4M/1.3 FT
 Seward, AK        0.4M/1.3 FT   Kodiak, AK       0.7M/2.3 FT
 Wave heights are expected to peak approximately two hours
 after initial arrival.

Time - Time of measurement.
Amp. - Tsunami amplitudes are measured relative to normal sea level. It is NOT crest-to-trough wave height. Values are given in both meters (M) and feet (FT).

Tsunamis can be dangerous waves that are not survivable. Wave heights are amplified by irregular shoreline and are difficult to forecast. Tsunamis often appear as a strong surge and may be preceded by a receding water level. Mariners in water deeper than 600 feet should not be affected by a tsunami. Wave heights will increase rapidly as water shallows. Tsunamis are a series of ocean waves which can be dangerous for several hours after the initial wave arrival. DO NOT return to evacuated areas until an all clear is given by local civil authorities.

The Pacific Tsunami Warning Center in Ewa Beach, Hawaii will issue messages for Hawaii and other areas of the Pacific outside the states and provinces listed above.

This message will be updated in 60 minutes or sooner if the situation warrants. The tsunami message will remain in effect until further notice. For further information stay tuned to NOAA Weather Radio, your local TV or radio stations, or see the WCATWC web site.