Hawaiʻi County Hazard Mitigation

Tsunamis

Tsunmais are Hawaii’s most deadly natural hazard. They have killed more people in Hawaii than earthquakes, volcanic eruptions, hurricanes, and floods combined.

Two types of Tsunamis strike our coast:

Pacific-wide tsunamis: Created by large Earth-quakes, they travel to Hawaii from different areas like Asia, South America or Alaska.
Locally-generated tsunamis: Produced by geologic activity in the islands.

How are Tsunamis Monitored?

The Pacific Tsunami Warning System (PTWC) monitors earthquakes and measures tsunmai waves are seas. When a tsunami warning is issued, coastal sirens will sound. (Sirens are test on the 1st workday of every month at 11:45am.)

HOW TO AVOID BECOMING A VICTIM!

When you hear the sirens:
- Turn on your radio or local television station for more information. (*see map)
- If you are in a tsunmai evacuation zone, evacuate immediatetly and more to higher ground.
When a tsunami is generated locally:
- There may not be time for the sirens to sound before waves begin coming ashore.
- Your only warning may be to feel the ground shake from an earthquake or seeing the see suddenly withdraw or begin to surge inland.
If you feel a strong earthquake, move to higher ground immediately.

Do not return to coastal areas until you hear from County authorities.

Dangrerous tsunami waves may continue to come ashore for several hours.
No matter where a tsunmai originates, the waves will wrap around an island. All sides of our islands are at risk.

Remember: If you are in a low-lying coastal area, you are at risk from tsunamis.

Earthquakes

Over the last two centuries, Hawaii Island has been struck by several destructive earthquakes. In 2006, a major eathquake (magnitude 6.7) occurred deep beneath the northwest coast near Kiholo Bay resulting in an estimated $200 million in damage on the island.

HOW TO AVOID BECOMING A VICTIM!

Earthquakes cause destruction and loss of life by intense shaking. Knowing what to do could save your life.

If you are INDOORS during an earthquake, stay there!

Move quickly to a safe location, an inside corner of the room or under a strong table.
Stay away from glass, windows, outside doors, and anything that could fall.
DROP to the floor, COVER your head, HOLD ON and stay inside until the shaking stops. Most deaths and injuries occur when people inside buildings rush outside and are struck by falling debris.

If your are OUTDOORS during and earthquake, stay there!

Move to an open area away from buildings, utlity lines, and trees.
If you are driving, slow down and stop on the side of the road, but not under a bridge, overpass, power lines, trees, or large signs. Stay in your car.

Mountainous areas/slopes/cliffs:

Be alert for falling rocks and debris.

Beaches:

Move quickly to higher ground or several hundred yards inland. A local tsunami could strike.

Make sure you know what to do in an earthquake!

NOAA Weather Radio – a potential lifesaver

http://www.prh.noaa.gov/hnl/pages/nwr.php

Hurricanes and Windstorms

On Hawaii Island Northeast trade winds prevail throughout most of the year, generally blowing at 10-20 mph, but:

Strong gusty trades may reach 40-60 mph.
Storms approaching from the South and South East, called Kona storms, can produce hurricane strength winds.

Will a hurricane hit Hawaii Island?

Thus far the island has been spared from a major hurricane strike, but since 1950 five storms have caused extensive damage in the Hawaiian Islands.

HOW TO AVOID BECOMING A VICTIM!

Plan ahead:

Know the locations of the nearest designated hurricane shelters, usually public schools with reinforced buildings. When a hurricane warning is issued, Civil Defense will announce which shelters are open.
Prepare a family plan noting shelter locations and telephone numbers of friends and family on other islands, or the mainland, to use as a central contact point should you become separated or local phone service is saturated.

When a hurricane or tropical storm warning is issued:

Follow instructions issued by Civil Defense and monitor radio or local television for advisories, watches, warnings and update information. (*See map)
If time peermits, complete preparation activities. Board up windows and store loose objects.
Evacuate to the nearest shelter if you are in a low-lying coastal area, along ridge lines exposed to strong winds, in an area subject to stream flooding, or in a wooden of lightly constructed building.

If ordered to evacuate, leave immediately!

Remember: Hurricane Season in Hawaii is June 1st – November 30th. A Hurricane or Tropical Storm Warning means hurricane or tropical storm conditions are expected to occur within 36 hours. Be prepared.

Storm Surge

The greatest loss of life due to hurricanes is caused by coastal flooding known as storm surge. In Hawaii, water levels rise primarily from high waves generated by storm winds and from low atmospheric pressure near the eye of the storm. Storm surge is often amplified as streams flooded by heavy rain empty into the ocean. Large, unpredictable waves and strong erratic coastal currents make any form of ocean activity dangerous.

HOW TO AVOID BECOMING A VICTIM!

Never go near the ocean near a tropical storm or hurricane.
Evacuate low-lying areas when advised by local authorities.

Rainfall Flooding

Flash floods are the leading cause of direct weather-related deaths in the State of Hawaii. The Big Island averages a damaging flood, caused by heavy rainfall, everey two years.

Why are floods so dangerous?

Flash floods can occur withing a few hours or even minutes of excessive rainfall.
People underestimate the force of water. Six inches of fast moving water can knock you off your feet, and 2 feet of water will float your car!
Deaths occur when people are caught in rapidly rising flood waters.

HOW TO AVOID BECOMING A VICTIM!

Listen to your radio for the latest flash flood Watches, Warnings, and Advisories. (*See map)
Do not camp or park your vehicle along streams during threatening conditions.
If the vehicle stalls, leave it immediately and seek higher ground.
Never try to walk, swim or drive through flood waters.
If you come upon flood waters, STOP! You will not know the depth of the water nor will you know the condition of the road under the water.

Turn Around, Don’t Drown!

High Surf

In Hawai‘i more injuries are caused by high surf than by any other coastal hazard. High surf (10-20 feet) arrives along north facing shores each winter. Large waves (4-6 feet) strike south shores during summer months.

HOW TO AVOID BECOMING A VICTIM!

No matter how strong a swimmer you think you are, remember Hawai‘i’s surf is among the most powerful on earth.
Large surf often generates powerful rip currents that no one can swim against.
Swim only at beaches with lifeguards. Check with them about ocean conditions prior to going into the water.
Watch the surf for at least 15 minutes to allow time to see a large set of waves and judge how big the surf is.

If in doubt, don‘t go out.

Volanic Hazards

One of nature’s most spectacular sights is lava entering the sea. When lava pours into the ocean, seawater flashes into steam causing spectacular explosions and blasting hot rocks, hot water, and molten lava fragments hundreds of feet into the air, out to sea and inland.

Be Alert to Danger

Lava entering the sea is often hidden beneath a plume of steam, luring visitors too close for safety. Newly formed lava shorelines can collapse generating large waves and blasts blasts showering large lava rocks both inland and out to sea.

HOW TO AVOID BECOMING A VICTIM!

Always follow approved, marked pathways.
Stay at least 1.200 feet away from where lava enters the sea.
Exercise caution if you have heart or respiratory ailments, such as chronic asthma. Acid fumes. cinders and ash particles within the steam plume can irritate eyes and lungs.
Be alert when observing lava entering the sea. Second degree burns can occur from hot ocean water near the entry or water splashed by large waves.

Safety First when watching lava enter the sea.