"Sitka TSUNAMI Preparedness Information"
Prepared by the Sitka Fire Department and LEPC
for the City and Borough of Sitka
Tsunami
Pronounced (soo-Nah-Mee), and often erroneously called tidal waves, they are actually a series of traveling ocean waves of great length and long period, generated by disturbances associated with earthquakes in oceanic and coastal regions. As the tsunami crosses the deep ocean, its length from crest to crest may be several miles to a hundred miles or more, and its height from trough to crest only a few feet. In deep water, tsunami waves can reach speeds up to 600 miles per hour. As the tsunami enters the shallow coastal waters, its speed decreases while its height increases.
The Alaska Tsunami Warning Center
The ATWC is the nerve center for a network of remote seismic stations in Alaska, Washington, California, Colorado, and other areas. When a large earthquake occurs near the North Pacific coast, an automated system and geophysicists at the ATWC rapidly determines its location (epicenter) and magnitude. If the earthquake is considered to be great enough to generate a tsunami, the ATWC will issue an immediate TSUNAMI WARNING for a limited area.
This warning is sent to Alaska through the military, Coast Guard, National Weather Service, Alaska Division of Emergency Services, Federal Aviation Administration and other agencies.
The Alaska Tsunami Warning Center will begin issuing its WARNING within approximately 15 minutes of a quake, but that is not quick enough for locally generated tsunamis, so when in doubt evacuate.
Local Tsunamis
In Alaska, the most serious threat is from a local tsunami, because these are generated immediately offshore by landslides, mudslides, and avalanches. They may also be created if a pier or bridge collapse. This is especially dangerous in enclosed harbors. The water will have a bathtub effect and will wash back and forth from shore to shore creating havoc and potential loss of life. They can strike the coast in only a few minutes. Local Tsunamis may not be monitored or indicated by the ATWC. Most local tsunamis are reported from observation.
How to Prepare
Creating a family emergency kit is a great way to prepare for any emergency. The following is a list of suggestions that you can add to or subtract from while you are building your own personal kit that suits you or your family.
- Water - At least 5 gallons per person, stored in clean plastic containers, in a cool, dark location. Change out the water in each container every six months.
- Food - Keep at least 3 days worth of canned food on hand, and rotate it in with your regular stock every 6 months. Also the local sporting goods stores sell Meals Ready to Eat (MRE), and freeze dried foods which keep for a long time.
- Baby formula, if you have infants
- Pet Food, don't forget them
- Manual can opener
- Flashlight with extra batteries
- Radio with extra batteries
- First Aid Kit
- Camp stove
- Sleeping Bags
- Matches /Lighters
Evacuation Routes
Tsunami evacuation route signs are posted on inbound routes of Halibut Point Road to Kashevaroff St., Sawmill Creek Road to Lake St., Japonski Island to Lake St., and outbound from the general town area to either Peterson Ave. or Lake st: These signs will lead you to the predesignated staging areas of Sitka High School and Verstovia Elementary School.
During a Tsunami emergency your Local Emergency Management office, Police, Fire Department, and other emergency organizations will try to help you. Give them your fullest cooperation.
Do not call 911. This ties up all incoming emergency phone lines and prevents dire emergencies from being reported.
Local authorities will tell you when the danger of a tsunami has passed. Also stay tuned to your radio, marine radio or NOAA weather radio during a tsunami emergency.