“Maui Weather can be extreme, and catch the unwary person off guard. Knowing the signs of extreme weather and the right actions to take will help you handle these situations and avoid severe consequences. Here are a few of Maui most extreme weather phenomena” Ride Safe and have fun”. David Dorn

Maui Weather can be extreme, there events both rare and common that can appear suddenly and will have extremely serious consequences for the unwary sailor. In some cases you will have only a few minutes to react. Knowing what is happening, and what to do could save your life. For safety reasons you should always be aware of: extreme weather, severe weather, and any marine warnings. Check the weather reports before going to the beach, so you will have a good idea what to expect when you get there. 

Extreme Weather on Maui About Maui Wind Gusty Wind High Wind Shore break
Storm Surge Vog Flash Flood Landslides Offshore Winds
Kona Storms Maui Snow Black Snow El Niño Surging Waves
Hurricane Season Tsunami Dust Devils Earthquake Water Spouts
Huge Surf Rogue Waves Tropical Storms Thunder Storms Rain Squalls
Cane Smoke Pyrocumulus cloud     Brown Water

Extreme weather on Maui is the norm:

When participating in ocean sports and wind sports on Maui you should be prepared for the extremes of wind and waves that you are likely to meet. Sometimes called the Maui factor, it usually translates to Maui will be more extreme than anything you are used to. Many mainland surfers come to Hawaii and get their butts kicked because of the significantly more powerful surf here. Wind sports too. Many windsurfers and kiters who consider themselves experienced or expert in their local areas will get a serious attitude adjustment when riding on Maui for the first time. Maui just has a combination of natural attributes that bless it with phenomenal weather (a blessing that is if you like big waves and strong wind). Check out the “What Makes Waves” page, and the “Maui Wind Report” Page, for the basics of what factors produce these extreme conditions. Once you have a basic understanding, of the forces at work, you can better appreciate the specific weather phenomena that is described below.

Maui Wind is a Combination of at Least Five Factors:

  1. Tradewind Effect.
  2. Sea Breeze Effect,
  3. Venturi Effect, 
  4. Bernoulli Effect,
  5. and Weather related winds (such as storms).

Each of these factors has an influence on the Maui winds and can combine to create extremes of wind that are especially fierce on Maui.

High Winds: The most common weather extreme that you will encounter on Maui is High Wind. Regular trade winds are funneled by the island’s geography and accelerated into some very frequent high winds. These winds are many times more powerful than regular trade winds, and wind experienced in other locations. Even on a nice sunny day the trades can reach speeds in excess of 40knots, gale force. This catches people off guard because they usually only encounter such winds associated with storms and nasty weather (where they are usually indoors anyway). Wind strength increases with the square of its velocity. This means when you double the wind speed, you QUADRUPLE the power. If the wind speed doubles you might want a sail one quarter of the size you were using.
Gusty Winds: If you have ever looked at a wind speed chart you will see that the line is very rarely straight. Wind usually goes up and down is a series of gusts and lulls. The wind speed given is usually just the average of the highs and the lows. The best kind of wind for wind sports is smooth and steady winds. The hardest wind to handle is a gusty wind, with its high highs and low lows. When you see a detailed wind chart for the area, take note of the minimum and maximum numbers. If these two numbers are close together, it will be good steady wind. If the two numbers are far apart it will be rough gusty wind that is difficult to sail in. Gustiness’ is caused by unstable atmosphere, or interrupted airflow from obstacles of landforms. Gusty wind can be caused by clouds and rain squalls. If the wind is blowing onshore from the unobstructed ocean, it is usually more steady than a wind that lows side-offshore. The side-off wind has to contend with obstacles on land and will tend to make it more gusty. Avoid Gusty conditions, and avoid offshore winds, and rain clouds. Take care when sailing in side shore wind in evenings, because they sometimes turn offshore and gusty closer to nightfall. Sometimes wind will tend to shut off at nightfall. This is especially common in Kihei and dusk in a NE trade wind. Many sailors have been stranded when the wind suddenly died at sunset.
Rain Squalls: When it rains the downpour can cause a outflow of air beneath the cloud. The downdraft caused by the mechanical action of the rain and the cooling effect, often create an outward push of air called a “gust front”. When sailing you should always keep an eye out for rain clouds, and expect a sudden increase in wind at the leading edge of a cloud or rain squall. Gust fronts come suddenly and can be extremely intense. If possible return to shore quickly and wait for the gust front to pass. It is safer to avoid rainy weather altogether. If you are caught out during a rain squall, then it is best to keep your sail/kite down on the water and wait for the squall to pass.
Thunder Storms: Thunder storms are intense and dangerous events. Although we do not seem to have as many thunderstorms here in the islands as there are on the mainland, the ones here can be just as dangerous. Any thunder storm should be considered as an extreme weather event. Always avoid being outdoors during any thunderstorm. Watch the weather when planning any activities. Unstable weather especially during cold fronts can increase the frequency of thunderstorms. Keep and eye out for vertical cloud formation, high vertical cumulonimbus clouds can signify a thunderstorm, although these could be obscured by a lower cloud layer. Listen for thunder and lightning, and get indoors. Do not sail, surf, or kite (or play golf) in a thunderstorm. There is a danger from extreme winds and lightning strike. Lightning strike can also occur far from the rain and clouds up to several miles away. Sometimes lighting strikes can be preceded by static electricity buildup than can be felt. Some estimates say that worldwide up to 250,000 people are injured by lightning each year. In the US about 500 people get injured by lightning and 50 of those people die (on average) from lighting strikes each year. be smart and don’t take risks with thunderstorms so don’t become one of these statistics. When you hear thunder stop all outdoor activities, and try to get indoors into a substantial building, otherwise get inside your full body car or truck, and do not touch any metal parts. Do not get under any vehicle, or shelter in a convertible or soft-top car. Stay away from windows and TVs and computer screens. And avoid metal plumbing fixtures. [“When thunder Roars get indoors, use your brain don’t wait for rain”].
Offshore Winds: The extreme offshore winds will be a lot more powerful that they appear. The water close to the beach will usually appear calm because of the wind shadow created by the trees and land form. But just a short distance offshore the wind can be extremely strong and push a surfer and kayaker out to sea faster than they can possibly paddle. They say as many as 30 kayaks are lost out to sea every year from the leeward side of Maui. If you are caught in an offshore wind in a Kayak (or SUP etc.) you should stay with the kayak even if you are getting blown far away from shore. Do the international distress signal waving your arms overhead and maybe put a tee shirt on a raised paddle as a marker flag making you easier to see. Some people panic and decide to abandon their kayak and try to swim to shore. This is very risky because you as a lone swimmer are virtually impossible for rescuers to see, and you may have underestimated the distance to swim to shore. People can more easily survive drifting overnight on a kayak, or windsurfer blown away from shore. Sometimes for days. People swimming are more likely to perish. In a strong trade wind you may be able to drift towards Lanai’s shipwreck beach, or make landfall on Molokini or Ko’ohalawe. Maybe take along a cell phone in a waterproof bag. Professional kayak guides also carry waterproof VHF radios and EPIRB  (Emergency Position Indicating Radio Beacons) beacons.
Dust Devils: Occasionally on still days with clear skies hot humid conditions and variable winds. You may see a column of dust rising up from a freshly plowed cane field. The hot rising air pierces up through a layer of cooler air above and carries the loose red dust a hundred feet or so. These mini twisters can also occur in overcast weather with cloudy unstable atmospheric conditions. These mini-tornadoes can be quite intense in localized areas, and are best avoided and/or viewed from a distance. Direct contact with a dust devil can cause damage to fences, garden furniture, tool sheds, dog houses or whatever else is not bolted down. Dust devils can cause injury to people by throwing debris around. Dust devils can occur anywhere and can be almost invisible. Especially over hard surfaces like the city.

Waterspouts: Like the dust Devil, waterspouts are mini twisters that can last a few minutes up to half an hour. They occur over water and can suck up water to incredible heights. Sometimes several; waterspouts will happen together. Waterspouts are an indication of unstable weather, and usually stormy clouds. They are the result of vertical forces in the air flow often associated with heat energy at the surface. During low pressure events, like storms or cold fronts. Waterspouts are bad news for sailors, especially windsurfers and kiters and are best avoided. If you see a waterspout it is best to retire from sailing for the day, or at least until the weather has passed. People, especially kiters have been seriously hurt/killed by updrafts and extreme gusts in this type of weather. The waterspout is associated with unstable dangerous weather. The intensity of the wind at the center of the waterspout could seriously injure a person who was unlucky enough or stupid enough to come into contact with it. Waterspouts can come onto the land and have even greater destructive power than your average dust devil. The wind vortices that create visible waterspouts, are only visible when they suck up water or other debris into the air. There may be several other invisible vortices that you cannot see.  You can sometimes observe the formation of a waterspout by looking at the bottom of a cloud layer, as is begins to dip downward in a conical shape.


Gale Warning:

A warning of 1-minute sustained surface winds in the range 34 knots (39 mph or 63 km/hr) to 47 knots (54 mph or 87 km/hr) inclusive, either predicted or occurring and not directly associated with tropical cyclones.

High Wind Warning:

A high wind warning is defined as 1-minute average surface winds of 35 knots (40 mph or 64 km/hr) or greater lasting for 1 hour or longer, or winds gusting to 50 knots (58 mph or 93 km/hr) or greater regardless of duration that are either expected or observed over land.

Hurricane Warning:

A warning that sustained winds 64 knots (74 mph or 119 km/hr) or higher associated with a hurricane are expected in a specified coastal area in 36 hours or less. A hurricane warning can remain in effect when dangerously high water or a combination of dangerously high water and exceptionally high waves continue, even though winds may be less than hurricane force.

Hurricane Watch:

An announcement for specific coastal areas that hurricane conditions are possible within 48 hours.

Storm Surge:

An abnormal rise in sea level accompanying a hurricane or other intense storm, and whose height is the difference between the observed level of the sea surface and the level that would have occurred in the absence of the cyclone. Storm surge is usually estimated by subtracting the normal or astronomic high tide from the observed storm tide. Storm surge can add several feet to the expected tidal height. if this occurs during a high tide, the water level becomes high enough to inundate the land. this can allow waves to break farther inland and can cause flooding to low lying areas, and also allow waves to undermine sandbanks, and shoreline structures. The storm surge is one of the factors that makes hurricanes so destructive.


El Niño: El Niño is a temporary disruption in the normal interactions of ocean and atmosphere in the pacific ocean. The El Niño is triggered by a temperature increase in the eastern pacific. When the water is measured at 0.5 degrees above normal for three consecutive months than an El Niño is predicted. El Niño conditions can lead to a chain of weather changes and detrimental effects to fisheries in the area. El Niño also causes increases flooding rains as far north as California, and a disruption in the regular trade winds in Hawaii. During an El Niño year the trade winds in Hawaii are weakened, due to the high pressure systems moving southward. El Niño in Hawaii can also mean; lower rainfall, drought like conditions and an increase in hurricane activity. El Niño may increase swell producing storms, and increase the wind strength during storms., The El Niño is part of a larger oceanic cycle that occurs every two to seven years. The last El Nino was late 2009/early 2010, while the last one NOAA predicted was in 2012 but never quite materialized. There is also a possibility of El Niño conditions developing in summer 2014.

What are Tradewinds?: In summer the trade wind weather predominates. Trades blow from the NE to ENE direction and provide the comfortable climate and wind powered activities that we enjoy here in the islands. In summer 9 out of 10 days have trade winds. Trades usually bring fair weather to the central valley and south side of the island. But trades do bring regular showers to the windward sides of all the islands and on Maui especially toward Hana, Haiku and upcountry. We do have the rainforests and waterfalls to prove it. Showers are especially frequent in overnight and in the mornings. There may be spells of lighter winds but Hawaii has a high number of windy days.
Kona Storms: bad weather on Maui often comes from the south. Low pressure systems to the north will bring wind and rain and larger surf to the south shores on Maui. These areas are not used to these conditions, The conditions happen so infrequently that when they happen they catch people and infrastructure off guard. The leeward southern sides of the island are usually clear, dry and have small surf. When a Kona Storm occurs, the rain can quickly overwhelm the storm drains, and cause localized flooding, and block roads, and sweep debris into the sea. The water will usually get muddy quickly and may be contaminated with sewerage runoff caused by excess rainwater. Streams quickly flood and the coast line becomes unsuitable for snorkeling, swimming and other activities. It is best to avoid these beaches during Kona Storms. In a Kona Storm the wind flow across Maui is reversed from its usual trade wind NE direction. this makes the North shore the lee side, with accelerated strong offshore conditions, that make surfing, windsurfing, and kiting potentially dangerous. Depending on the severity of the storm and the associated wind conditions, most people are better off staying out of the water all together.


Vog: Vog is the name given to Volcanic Fog. The active eruption (since 1983) of the Kīlauea volcano, on the Island on the Big Island, is estimated to emit 2,000–4,000 tons of sulfur dioxide every day. Sulfur dioxide is the major component of Vog. During times of light wind or southerly Kona wind, the volcanic haze from the big island is brought up and across Maui. Maui suffers reduced visibility, and the air becomes thick with a yellowish tinge. Vog can be a big problem for people with breathing difficulties, especially the elderly and children. The air contains sulfur compounds and fine particles that react with oxygen & water vapor, and are eventually breathed in. To reduce the effects of Vog, stay indoors and keep the air conditioners on. In cases of people having severe reactions (example: breathing difficulties) to Vog then immediate medical assistance should be sought. Vog will persist as long as the stagnant (variable) or “Kona” wind conditions remain the same. It just takes a fairly strong trade wind or NW Kona wind to blow the Vog away and back out to sea again. The predominant Nor-Easterly trade winds usually keep Maui free from the effects of Vog. On the bright side Vog conditions do make for spectacular red/orange sunsets so get your camera ready.
Maui Snow: Yes it does snow on Maui. At the highest elevations on Mount Haleakala, around 10,000 feet, The have been snowfalls, ice accumulations and frost. The snow is sometimes visible from the shore and creates a beautiful white cap on the mountain. Driving conditions at the summit can be icy and hazardous. Sometimes people will go to the summit and collect snow in coolers and bring it home. I have been hit with snow balls while standing on the street corner in sunny Paia. Snow does not fall every year, but when it does it can stay around for a few days.
Black Snow: There is a different type of snow that Maui is famous for. It is the black Maui Snow which isn’t really snow at all, but is the black ash that falls like snowflakes after a cane burning. The Maui Snow has been falling on Maui for as long as there has been sugar cane burning (about 200 years). It looks like sugar cane production on Maui may soon be at an end. The Sugar cane uses way too much water, and the the economics no longer make sense. The Maui sugar producers have been losing money for a few years because the demand and price for sugar has dropped, while the demand for water has risen on Maui significantly. So we may one day in the future we could also be saying goodbye to the black snow too.
Cane Smoke: Many people complain of breathing difficulties during cane burns. There is a smart phone app to report cane smoke: The air pollution level is high, and the air contains smoke from the burnt cane as well as all the plastic irrigation tubing that also gets burned up along with the sugar cane. In more recent years the sugar company has also admitted to the aerial spraying large amounts of herbicide chemicals onto the sugarcane as a “desiccating (drying) agent” prior to burning. The chemical is a well known infamous herbicide that actually kills the sugar cane, so it dries out, and presumably makes it easier or cheaper to harvest. Sadly these chemicals can also be over-sprayed into neighboring homes, on pets and gardens, and can also get into water supplies, and find their way into the ocean, as well as getting burned up in the cane fires. So you really really do not want to breathe cane smoke.

Pyrocumulus cloud: Is a cloud associated with a fire or volcanic activity. Volcanic Pyrocumulus are seen on the big Island, and fire related are caused on Maui in many large  Sugar Cane-burning events. The intense heat and soot cause large clouds to form that are grey and brown, and billow high into the air. These clouds can look like mushroom clouds from nuclear explosions. The condensation may be accelerated from the large amounts of smoke particles providing nuclei for condensation of water droplets, the latent heat released during condensation helps to heat the air and drive the clouds higher. This creates a strong convection that mixes the smoke and pollution into more air layers. These clouds also are responsible for the transportation and distribution of toxic chemicals, and pollution over large areas and over great distances. Ultimately all of the pollution inside the clouds will either rain down or reach the ground downwind of the source.

Flash Floods: Maui’s steep mountains and deep ravines are very susceptible to flash flooding. Flash flooding occurs, where a large amount of rain runoff flows quickly down streams and gullies. The rain can be falling high up on the mountain sides and then cause flash floods far below. Hikers have to be especially wary of floods, but they can also affect drivers, because floods can wash out roads, or push across waterways. Never attempt to cross a flooded stream. Get to high ground and wait. Do not drive across flooded roadways. Cars are sometimes forced off the road and washed down the streams into the sea. “Turn around and don’t drown”. Also do not swim in any streams during heavy rainfall, or when there is a flash flood watch or warning. Streams can suddenly swell and rocks can get swept over waterfalls of fall off cliffs. Heavy rain can also lead to rock slides and mud slides. Be extremely careful in and around flood water. There is danger from  submerged debris, power lines, and dangerous currents.


Brown Water: After heavy rains and flash floods, the stream-water and ocean-water becomes muddy and brown. This condition is known as “brown water”. Brown water usually contains contaminated storm water runoff that can also include; overflow from septic tanks, pesticides, pathogens, as well as bacteria and debris. It is always recommend to stay out of brown water in streams and in the ocean. It will generally take a few days for brown water to clear. And allow time for the ocean to clean itself. Brown water and post-storm swimming should be avoided or restricted especially if people have any cuts or lowered immune systems. Brown water also attracts sharks and other marine predators. So “if its brown, don’t go down”.
Land Slides: Maui is made up of two conjoined shield volcanoes. The rocks and earth are put down in a series of layers. Each layer consists of fragmented lava and ash making for a fairly loose unstable geology. In addition to these layers there has been extensive erosion, and millions of tons of rock and rubble have eroded away from the original volcanic cones and been transported down hill. Deep valleys have been cut deep through the volcanic layers and created cliffs that are for the most part unstable. You will often see roadside cuttings that are reinforced with cages or metal nets that attempt to stabilize the rock faces. Rock falls are very common at roadsides, and near steep walls anywhere in Hawaii. The steeper the terrain the more rocks will fall. This is usually made worse by rain. Hawaii is also geologically active and there are hundreds of small earth tremors that may add to the problem. Because of the loose rocks in Hawaii, Maui we do not have rock climbing here, its too dangerous. Also beware when hiking any of the island’s valley trails, because rocks can fall from high above. And you may also be loosening rocks as you walk along higher trails that could slide down afterward. Also do not swim in any streams during heavy rainfall, or when there is a flash flood watch or warning. Streams can suddenly swell and rocks can get swept over waterfalls of fall off cliffs. Heavy rain can also lead to rock slides and mud slides.
Hurricane Season:       Hurricanes are rare but the hurricane season is from June to November. Hurricanes can occur at other times but are extremely rare. Hurricanes and Tropical Storms are fed by the interaction of warm ocean water and cold air. Hurricanes will lose their power if they cross over a large land mass like the continental US. However they present extreme danger to small islands by binging storm surge, high waves, in addition to destructive winds, and flooding rains. The last major hurricane to hit Hawaii was Iniki, which severely damaged Kauai in September 1992. Even remote hurricanes can bring bad weather to the islands. Hurricanes bring extremely heavy rains for days at a time, causing flash flooding and flooded roadways etc. Hurricanes can span hundreds of miles and their effects can be felt well in advance of the storms center. Hurricanes also feature extremely strong winds with the most severe winds at generally ahead of the eye wall. Hurricane strength winds begin at 74–95 mph, 119–153 km/h. Hurricanes are rated depending on their strength according to the Saffir-Simpson hurricane scale (SSHS). Category “One” is the lowest level, and five is the highest category with winds ≥157 mph, ≥252 km/h.  Even if a full strength hurricane weakens and is downgraded it is still conceded a severe weather event. Hurricanes can begin as Tropical Storms (TS) and grow into hurricanes or vice versa, depending the amount of energy gained or lost. Tropical Depression (TD) is a lower category with winds of <38 mph, <62 km/h. During hurricanes, power lines are downed, trees uprooted, and the water and power can be cut off, travel restricted, roads closed, planes grounded,  and can cause severe structural damage to houses and structures. Examples: Roofs get blown off, windows break etc. During hurricane season local residents prepare by storing water and food enough for several days of power outages, and loss or water. There are also evacuation centers set up, at various locations.
Saffir–Simpson hurricane wind scale
Category Wind speeds
Five ≥157 mph, ≥252 km/h
Four 130–156 mph, 209–251 km/h
Three 111–129 mph, 178–208 km/h
Two 96–110 mph, 154–177 km/h
One 74–95 mph, 119–153 km/h
Additional classifications
39–73 mph, 63–118 km/h
<38 mph, <62 km/h



Huge Surf: Maui gets its share of huge surf. During the winter months there will be several large surf events. Strong Storms in the northwest pacific generate huge swell systems that transmit energy towards the islands in the form of large wave trains. These trains can transfer storm energy thousands of miles to the islands. Waves at 50-60 feet are not uncommon. The outer reefs of the Islands get the largest waves. Closer to shore the waves are usually closing out along the entire coast. Regular surfing is not possible at the most exposed beaches. Surfing maybe possible around the sides of the island or in the bays or harbors. Surfers will look for the less powerful waves that are wrapping around the island. Some big wave surfers may attempt to go out in the biggest waves. using a few access points or towing out with jet skis to get beyond the white water. These surfers are highly trained, experienced, and are specialized to these conditions. Even with the correct gear and training they can still get into trouble in these waves.
Rogue Waves: Rogue waves are possible at any time. They are usually rare and unpredictable. Larger waves are less common than smaller rogue waves. Rogue waves can be caused by the effects of currents against winds in the ocean. Closer to shore, rogue waves are probably the result of several different swells interposing on each other and combining to produce a large freak wave.  Rogue waves are much larger that the largest expected waves of a set. They are defined as waves twice the size of the significant wave height (SWH). The SWH is the average of the largest third of the recorded waves. Because these waves are unexpected they will catch people off guard. Because they are so much larger that the average waves, they behave differently then the other average predicted waves. A large rogue wave can appear out of nowhere without warning, and break father out, get higher, be more powerful, and reach higher up the beach than other waves. A rogue wave can simply reach far up the beach and drag people back into the sea with the backwash. These are thought to be the biggest killer of rock fisherman around the world. During storms or significant waves events, large rogue waves are more likely to occur. Hawaii is no exception.
Surging Waves: Perhaps the biggest killer around the ocean are Surging waves. Every year thousands of people die whilst rock fishing or getting too close to the ocean, when they are taken by a surging wave. A wave does not have to break in order to be dangerous, A larger than average wave can rush ashore and come much farther up the shoreline than expected, and carry away anyone in its path. Because much rock fishing is done from rocky in accessible shoreline, there may be no way for someone who is swept into the sea from getting back onto the shore again. Someone in this situation may either drown or get smashed onto the rocks trying to come ashore. To avoid being a victim of surging waves. never get too close to the water unless you intend on getting wet. always be wary in large surf, and stay away from the soak zone. And Never turn your back on the Ocean.
Shore Break: Maybe this condition is too common to be called a weather extreme. But Shore Break is very dangerous condition that everyone should be aware of and take precautions around. At surf beaches the waves at the shoreline break onto the shore with great force. Even small waves a few feet high contain tremendous power with the weight and momentum of the water moving. Unsuspecting people are regularly injured by getting caught in the shore break. The danger of the shore break wave is getting knocked off your feet and being smashed into the sand. The waves force driving you into the sea floor can easily cause a broken arm, or head, back, and spinal injuries. This can happen in waves less than waist height. If you are not an experienced ocean swimmer be especially careful and swim in a swim zone patrolled by the lifeguards. If you are experienced in body surfing still be careful in shore break and do not spend any more time in the shore break than you need to. You may see some people playing in the shore break, perhaps local kids bodysurfing or skim boarding. But if you watch carefully you will see that they have mastered the timing of the wave and will usually flip over and land on their feet when the wave breaks. Local kids who are brought up in the ocean will make it look easy to swim in the shore break, but don’t be deceived. Even the strongest man is no match for the power of the wave if it turns against you. There are many beaches on Maui with little or no shore break, these beaches are best for casual swimming. The beaches with strong powerful shore break should be avoided. Big Beach (Makena beach in south Maui) has the worst reputation for serious injuries caused by Shore Break. Also notable beaches with strong shore break include; Baldwin Beach, D.T. Fleming, & Little Beach. Watch out for red Flags on beaches and warning signs posted by the lifeguards. Be doubly cautions on unpatrolled beaches.

TSUNAMIS in Hawaii:

The Hawaiian Islands are susceptible to tsunamis. Tsunamis are a series of large devastating waves caused by geological events, like earthquakes and undersea landslides. In the event of an undersea earthquake, large sections of seafloor can suddenly shift causing a huge displacement of water. Unlike regular waves that are an accumulation of smaller wind waves. Tsunamis are much larger and will breach the shoreline and inundate the land.

 When a Tsunami occurs, the wave may only be a few feet high while in the deep water but have a wave length of a hundred miles. The wave covers a huge area and contains a tremendous volume of water. The tsunami waves in the open ocean can travel an average of 450 to 600mph across the ocean and spread out from the epicenter. The arrival time at Hawaii depends how far away the epicenter was from the islands. The more distant it is the more warning time we might receive. Hawaii is equipped with an early warning system. The pacific tsunami center in Honolulu has seismographic sensors and computers tracking all seismic activity in the pacific. When they detect an earthquake, their computer models predict the tsunami and warnings go out to the islands. On Maui we have warning sirens that are used in case of emergency. These civil defense sirens are tested the first work day of every month at 11:45am. If you hear a siren you should turn on your radio, and listen for announcements.  Distant tsunamis may have several hours warning before their anticipated arrival. Locally generated tsunamis give little or no warning. If you feel an earthquake you should head away from the shoreline immediately, and go inland to higher elevations.  Local tsunamis may arrive within in a few minutes or 15minutes after an earthquake. Not all earthquakes create tsunamis, but if you feel one you should evacuate the coastline immediately. There is no defense against a Tsunami if you are caught in one. Maybe if you are in a sturdy multistory building you could climb to the higher floors. The sheer volume of water moving arrives at the shoreline and keeps flooding ashore. Where a regular wave will come and go in a few seconds, a Tsunami wave may keep rising for 15minutes or so. The volume of water behind the wave raises the sea level and pushes the wave ashore hundreds of feet to a mile or so depending on the elevation. The amount of run-up, depends on the shoreline. Narrowing Bays get a focused wave that run-up even more. Tsunamis arrive in sets of several waves and the second wave can be larger than the first. The time between tsunami waves can be 5-90 minutes. You should stay away from the coast line until the all clear signal is given. It could be several hours before the all clear is given. One visual danger sign for an imminent tsunami is a sudden drop in sea level. When the reef suddenly gets exposed and the sea level drops below several feet of more below normal levels that could be the beginning of a tsunami wave. The sea level can suddenly drop before the arrival of the first wave, and between subsequent waves. You may only have a few minutes to run to higher ground. Many tsunamis occur in the pacific, some larger and many smaller ones, that are just a few feet by the time they arrive in the islands. A smaller tsunami can still cause an effect similar to the tide rising and falling several times in hour or so. Another point to remember is that a tsunami is most devastating at the coast. People in boats in deep water offshore may not feel much effect from the tsunami, and it may pass beneath them raising the sea level just a few feet in deep water.

  • Before going to the ocean, check the weather reports for any warnings.
  • If you hear a Siren, get out of the water & turn on your radio.
  • If you feel an earthquake, get away from the coast.
  • If you see the sea level suddenly drop below normal, get away from the coast.
  • If you see a tsunami wave run inland, or climb to higher ground.
  • Stay away from the coast until the all clear is given. move quickly to higher ground
For more information what to do in an emergency go to Hawaii State Civil Defense Website:
DISCLAIMER: The user assumes the entire risk related to its use of this data.  This data is provided “as is,” and the author disclaims any and all warranties, whether expressed or implied, including (without limitation) any implied warranties of merchantability or fitness for a particular purpose. In no event will the author be liable to you or to any third party for any direct, indirect, incidental, consequential, special or exemplary damages or lost profit resulting from any use or misuse of this data.

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