Tsunami Warnings and Preparedness for Seaside, OR USA
What Is A Tsunami?
Tsunami (soo-NAH-mee): a Japanese word that means harbor wave; a sea
wave of local or distant origin that results from large-scale seafloor
displacements associated with large earthquakes, major submarine slides,
or exploding volcanic islands. Typically generated by seismic or volcanic
activity or by underwater landslides, a tsunami consists of a series of
high-energy waves that radiate outward like pond ripples from the area in
which the generating event occurred.
Not all earthquakes produce tsunamis. To generate a tsunami, an earthquake must occur underneath or near the ocean, be very large (approximately Richter magnitude 7 or greater), and create vertical movement of the sea floor. However, recent studies regarding the potential for a great Cascadia Subduction zone earthquake off the Washington, Oregon, and Northern California coastlines indicate the local tsunami waves may reach nearby coastal communities within minutes of the earthquake thereby giving little or no time to issue warnings.
How will I know if a Tsunami is coming?
- The West Coast/Alaska Tsunami Warning Center (WC/ATWC) is responsible for tsunami warnings for California, Oregon, Washington, British Columbia and Alaska.
- The Pacific Tsunami Warning Center (PTWC) provides warnings to international authorities, Hawaii, and U.S. Territories within the Pacific Basin.
- During a natural or human-caused disaster, the Emergency Management Division coordinates and facilitates emergency response and recovery in Clatsop County.
Dean Perez, Clatsop County Emergency Management Director
- Sign up here for ClatsopALERTS!
- Anyone can search Twitter for info by going to www.twitter.com and searching #tsunami.
The WC/ATWC and PTWC may issue the following bulletins:
- Information: A message with information about an earthquake
that is not expected to generate a tsunami.
Action to take: For information only, no tsunami generated.
- Advisory: An earthquake has occurred in the Pacific Basin, which
might generate a tsunami.
Action to take: Potential danger. Be prepared to take action. Be alert, listen to your weather radio or local emergency authorities.
- Watch: A tsunami was or may have been generated, but is at
least two hours travel time to the area in Watch status.
Action to take: Possible strong and dangerous currents. Be alert, listen to your weather radio or local emergency authorities.
- Warning: A tsunami was, or may have been generated, which could cause
damage; therefore, people in the warned area are strongly advised to evacuate.
Action to take: Danger! Run to higher ground. Follow emergency instructions. If you felt the ground shake, there could be little time to get to high ground.
If you're near a coastal beach, here are ways to know a tsunami may be imminent and you need to seek higher ground:
- A warning siren may sound.
- Seawater may recede quickly.
- The ground may shake, indicating an earthquake has occurred.
- Your NOAA Tone Alert radio issues a warning that a tsunami may be headed to your area.
- Sign up here for ClatsopALERTS!
- Sign up for Email and Text Mesage Tsunami Alerts from the West Coast Tsunami Warning Center
Tsunami Evacuation Maps
View Seaside Tsunami evacuation maps by clicking below:
Seaside OR, Tsunami Warning Test:
Read the publication Tsunami Preparedness in Oregon
Live on the Coast? Is your community TsunamiRead? Visit the TsunamiReady site!
The earthquake and resulting tsunami that struck Japan in March 2011 swept millions of tons of debris into the Pacific Ocean. While most of the material sank or dispersed, an unknown amount is projected to wash up on shore in the Pacific Northwest. As of June 2012, some items linked to the tsunami have already been found on Oregon beaches. Read more information on Tsunami Debris on the Oregon Coast
Evidence of past Tsunamis on the Washington Coast:
Tsunami evidence in tidal land on Washington Coast:
Exploring the evidence of past Subduction Zone Earthquake caused Tsunamis on the Pacific Coast. This was a public walking tour on April 14, 2012 at the river bank of the Naiwaikum River led by Brian Atwater a USGS geologist and arranged by the Pacific County Emergency Management Agency (PCEMA). The different color sands on the riverbank are evidence of the sudden land drop and tsunami after a subduction zone earthquake in year 1700. If you dig deeper you can see evidence of other buried soils that indicate older past land level change/tsunami events, the oldest found here was from year 400. This evidence has been corroborated with study of growth rings in local trees.
Geologists have found the stumps of Sitka spruce and red cedar that were poisoned when the land sank and seawater invaded ground that was formerly above the high tide level. Study of growth rings in the killed trees show that they grew their final layer of wood during the year 1700 quake. Videos by Mike Challis 642weather.com
Tsunami Related links ...
Pacific County Emergency Management
Pacific County Emergency Management - Press Release Blog
Washington State Emergency Management Division
National Weather Service NOAA Weather Radio
National Weather Service NOAA All-Hazards Emergency Messages
Special Needs NOAA Weather Radio for Deaf and Hard-of-Hearing Individuals
Emergency Alert System (NOAA)
Emergency Alerting System (Washington State Emergency Management)
FEMA for Kids - NOAA Weather Radio
Washington Association of Broadcasters - Emergency Alert System
American Red Cross (Capital Area Chapter) -NOAA Weather Radio