Building a Weather-Ready Nation
Tsunami Preparedness
Tsunamis
• A tsunami is a series of powerful
waves accompanied by unusually
strong currents.
• The first wave may not be the largest
or most damaging.
• A tsunami can strike any ocean coast
at any time.
• Tsunamis are a serious threat to life
and property on the coast.
• Even small tsunamis can be
dangerous, especially to swimmers,
surfers, and boats in harbors.
• Tsunamis cannot be prevented.
www.weather.gov/tsunamisafety
But, there are things you
can do to keep yourself and
your loved ones safe in the
event of a tsunami!
Building a Weather-Ready Nation www.weather.gov/tsunamisafety How a Tsunami Works
Most tsunamis are caused by large earthquakes below or near the ocean floor, but they can also be caused by landslides, volcanic activity, certain types of weather, and near-earth objects (e.g., asteroids, comets).
1 2
A plate shifts abruptly, causing an earthquake and
displacing the water.
Waves are generated and move out in all directions across the ocean, some traveling as fast as 600 mph.
As waves enter shallower water, they compress, their
speed slows, and they build in height.
The wave height increases, and associated currents
intensify, becoming a threat to life and property.
Tsunami Preparedness
3 4
Building a Weather-Ready Nation www.weather.gov/tsunamisafety Tsunami Preparedness
Know Your Risk
In the U.S., tsunami risk is greatest for
states and territories with Pacific and
Caribbean coastlines. Ask your local or state
emergency management office or your local
National Weather Service office about your
community’s tsunami risk.
Links to tsunami evacuation maps:
http://nws.weather.gov/nthmp/maps.html
Building a Weather-Ready Nation www.weather.gov/tsunamisafety www.tsunami.gov
Tsunami Preparedness
Understand U.S. Tsunami Alerts
Take Action—Danger! A tsunami
that may cause widespread flooding is expected or
occurring. Dangerous coastal flooding and
powerful currents are possible and may continue
for several hours or days after initial arrival.
Follow instructions from local officials.
Evacuation is recommended. Move to high
ground or inland.
Warning Take Action—A tsunami with
potential for strong currents or waves dangerous
to those in or very near the water is expected or
occurring. There may be flooding of beach and
harbor areas. Stay out of the water and away
from beaches and waterways. Follow
instructions from local officials.
Advisory
Be Aware—A distant earthquake has
occurred. A tsunami is possible. Stay tuned for
more information. Be prepared to take action if
necessary.
Watch Relax—An
earthquake has occurred, or a tsunami warning,
advisory or watch has been issued for another part
of the ocean. Most information statements indicate
there is no threat of a destructive tsunami.
Note: Tsunami warnings, advisories, and watches may be updated or cancelled as information becomes available.
Advisories and watches may be upgraded if the threat is determined to be greater than originally thought.
Information Statement
Official warnings are broadcast through radio, TV, and wireless emergency alerts.
They may also come through outdoor sirens, officials, text message alerts, and telephone notifications.
Building a Weather-Ready Nation
Respond to a Natural Warning
Natural tsunami warnings are as important as
official warnings. There may not be time to wait
for an official warning. If you are in a tsunami
hazard zone and:
• Feel a strong or long earthquake,
• See a sudden rise or fall of the ocean, or
• Hear a loud roar from the ocean,
A tsunami could arrive in minutes. Take action!
• In case of an earthquake, protect
yourself. Drop, cover, and hold on.
• When you can move safely, move quickly
to high ground or inland.
• Stay out of the tsunami hazard zone until
officials say it is safe.
www.weather.gov/tsunamisafety
Tsunami Preparedness
Photo: COMET
Building a Weather-Ready Nation
Prepare for a Tsunami
These simple steps could save your life and the
lives of those you care about.
If your home, school, workplace, or other places
you visit often are in tsunami hazard zones:
• Have multiple ways to receive warnings.
• Make an emergency plan; include family
communication and evacuation plans.
• Map out routes to safe places on high
ground or inland; practice walking them to
make them familiar.
• Put together portable disaster supplies kits
for home, work, and cars.
If you are visiting the coast, find out about local
tsunami safety. Your hotel or campground
should have this information.
www.weather.gov/tsunamisafety
Tsunami Preparedness
Be a role model. Share your
knowledge and plans with others!
Make a plan
Practice evacuation
Credit: FEMA