A sneaker wave, also known as a sleeper wave, or in Australia as a king wave, is a disproportionately large coastal wave that can sometimes appear in a wave train without warning.
A sneaker wave, also known as a sleeper wave, or in Australia as a king wave, is a disproportionately large coastal wave that can sometimes appear in a wave train without warning.
The term "sneaker wave" is popular rather than scientific, derived from the observation that such a wave can "sneak up" on an unwary beachgoer. There is no scientific coverage of the phenomenon as a distinct sort of wave with respect to height or predictability as there is on other extreme wave events such as tsunamis or rogue waves, and little or no scientific evidence has been gathered to identify, describe, or define sneaker waves. Although the term "rogue wave" — meaning an unusually tall or steep wave in mid-ocean — is sometimes used as a synonym for "sneaker wave," one American oceanographer distinguishes "rogue waves" as occurring on the ocean and "sneaker waves" as occurring at the shore, [1] while the National Oceanic and Atmospheric Administration loosely defines rogue waves as offshore waves that are at least twice the height of surrounding waves and sneaker waves as waves near shore that are unexpectedly and significantly larger than other waves reaching shore at the time. [2] Scientists do not yet understand what causes sneaker waves, [3] and their relationship to rogue waves, if any, has not been established.
In a 2018 paper, Oregon State University researchers wrote that sneaker waves form in offshore storms that transfer wind energy to the ocean surface. The resulting waves then arrive along a coastline during periods of calm weather, and the greater amount of energy they contain compared to the regular waves that preceded them causes them to travel far higher up the shore than the other waves. [4] As of 2021, the National Weather Service in the United States viewed ocean conditions along the United States West Coast as favorable for sneaker waves when an offshore storm generates waves with a particularly long period — perhaps longer than 15 seconds — between swells, allowing the swells to build considerable force before reaching shore, where they might appear either as conventional large waves or as sneaker waves. [5]
Sneaker waves appear suddenly on a coastline and without warning; [6] generally, it is not obvious that they are larger than other waves until they break and suddenly surge up a beach. A sneaker wave can occur following a period of 10 to 20 minutes of gentle, lapping waves. [6] Upon arriving, a sneaker wave can surge more than 150 feet (50 m) beyond the foam line, rushing up a beach with great force. [6] In addition to containing a large volume of rapidly surging water, a sneaker wave also tends to carry a large amount of sand and gravel with it. It can be strong enough to break over rocks and float or roll large, waterlogged logs lying on the beach weighing several hundred pounds, moving them up the beach during the landward surge and then back down toward the ocean as the wave retreats. [6] Sneaker waves appear to be more common along steep coastlines than in areas with broader, more gently sloped beaches. [6]
The unpredictability of sneaker waves and their tendency to arrive suddenly after lengthy periods of gentle, lapping waves makes it easy for them to surprise unwary or inexperienced beachgoers; [6] because they are much larger than preceding waves, sneaker waves can catch inattentive swimmers, waders, and other people on beaches and ocean jetties and wash them into the sea. The force of a sneaker wave's surge and the large volume of water rushing far up a beach is enough to suddenly submerge people thigh- or waist-deep, knock them off their feet, and drag them into the ocean or trap them against rocks. [6] Many coastlines more prone to sneaker waves lie in colder parts of the world where beachgoers tend to wear heavier clothing; the amount of sand and gravel in a sneaker wave can quickly fill such clothing and footwear such as boots with sediment that weighs a person down as he or she is swept up a beach and then back into the sea, increasing the chances of drowning. [6] Floating and rolling logs in a sneaker wave also pose a danger, as they can badly injure people as well as pin people down when they come to rest, and it can be difficult or impossible to move such a log before a person pinned by it drowns as later waves arrive and fill the person's lungs with water and sediment. [6]
Sneaker waves are mainly referred to in warnings and reports of incidents for the coasts of Central and Northern California (including the San Francisco Bay Area's beaches, especially Ocean Beach, [7] Baker Beach, [8] and those that face the Pacific Ocean) [9] (e.g. from Big Sur to the California–Oregon border), Oregon, and Washington in the Western United States. [10] [11] [12] [13] [14] [15] Sneaker waves also occur on the coast of British Columbia in Western Canada, especially the province's southern coast, because they commonly occur on the west coast of Vancouver Island (including Tofino, Ucluelet, and Cape Scott Provincial Park). [16] [17] [18] [19] Sneaker waves are common on the southern coast of Iceland, and warning signs were erected at Reynisfjara and Kirkjufjara beaches, following three unrelated tourist deaths at those beaches over several years, the third of them in January 2017. [20] In Australia, where they are known as "king waves," sneaker waves occur especially in Western Australia and Tasmania, where they can be a hazard for rock fishermen. [21]
Along much of the United States West Coast, sneaker waves kill more people than all other weather hazards combined. [6] In Oregon, 21 deaths were attributed to sneaker waves from 1990 through March 2021, [3] most of the deaths occurring between October and April, although sneaker waves also occurred at other times of year. [3]
A sneaker wave incident gained worldwide media attention when two large waves suddenly and unexpectedly struck a crowd watching the Mavericks surfing competition at Mavericks in Princeton-by-the-Sea, California, on February 13, 2010, breaking over a seawall onto a narrow beach and injuring at least 13 people. [2] [22] The incident was caught on film. [2] [23]
In March 2014, a massive wave struck Roi-Namur in Kwajalein Atoll in the Marshall Islands on an otherwise calm, sunny day, penetrating well inland, flooding parts of the island and swamping coastal roads. [24]
On September 18, 2023, a sneaker wave smashed into a beachside restaurant at Marina Beach near Southbroom, South Africa, injuring seven people. One restaurant patron was swept out to sea but rescued by lifeguards. The wave was filmed. [25]
Rio de Janiero's Barra de Tijuca beach in Brazil experiences sneaker waves, known locally as ressaca waves. It also is a steep beach and a December 2023 news film shows the whole beach being cleared by a sneaker wave.[ citation needed ]
On 20 January 2024, one or more sneaker or rogue waves struck the United States Army′s Ronald Reagan Ballistic Missile Defense Test Site on Roi-Namur in Kwajalein Atoll in the Marshall Islands, breaking down the doors of a dining hall, knocking several people off their feet, moderately to severely damaging the dining hall, the Outrigger Bar and Grill, the chapel, and the Tradewinds Theater, and leaving parts of the island, including the automotive complex, underwater. The flooding of the dining hall was filmed. The wave or waves penetrated 300 feet (100 m) inland and probably were between 29 and 40 feet (8.8 and 12.2 m) tall amid a significant wave height of 10 feet (3 m) to 15 feet (5 m). [26]
In many parts of the world, local folklore predicts that out of a certain number of waves, one will be much larger than the rest. "Every seventh wave" or "every ninth wave" are examples of such common beliefs that have wide circulation and have entered popular culture through music, literature, and art. [27] [28] These ideas have some scientific merit, due to the occurrence of wave groups at sea, [29] but there is no explicit evidence for this specific phenomenon, or that these wave groups are related to sneaker waves. The saying is likely derived more from a cultural fascination with certain numbers,[ citation needed ] and it may also be designed to educate shore-dwellers about the necessity of remaining vigilant when near the ocean.
The coast, also known as the coastline, shoreline or seashore, is defined as the area where land meets the ocean, or as a line that forms the boundary between the land and the coastline. Shores are influenced by the topography of the surrounding landscape, as well as by water induced erosion, such as waves. The geological composition of rock and soil dictates the type of shore which is created. The Earth has around 620,000 kilometres (390,000 mi) of coastline. Coasts are important zones in natural ecosystems, often home to a wide range of biodiversity. On land, they harbor important ecosystems such as freshwater or estuarine wetlands, which are important for bird populations and other terrestrial animals. In wave-protected areas they harbor saltmarshes, mangroves or seagrasses, all of which can provide nursery habitat for finfish, shellfish, and other aquatic species. Rocky shores are usually found along exposed coasts and provide habitat for a wide range of sessile animals and various kinds of seaweeds. In physical oceanography, a shore is the wider fringe that is geologically modified by the action of the body of water past and present, while the beach is at the edge of the shore, representing the intertidal zone where there is one. Along tropical coasts with clear, nutrient-poor water, coral reefs can often be found between depths of 1–50 meters.
Surfing is a surface water sport in which an individual, a surfer, uses a board to ride on the forward section, or face, of a moving wave of water, which usually carries the surfer towards the shore. Waves suitable for surfing are primarily found on ocean shores, but can also be found in standing waves in the open ocean, in lakes, in rivers in the form of a tidal bore, or in wave pools.
A tsunami is a series of waves in a water body caused by the displacement of a large volume of water, generally in an ocean or a large lake. Earthquakes, volcanic eruptions and other underwater explosions above or below water all have the potential to generate a tsunami. Unlike normal ocean waves, which are generated by wind, or tides, which are in turn generated by the gravitational pull of the Moon and the Sun, a tsunami is generated by the displacement of water from a large event.
A beach is a landform alongside a body of water which consists of loose particles. The particles composing a beach are typically made from rock, such as sand, gravel, shingle, pebbles, etc., or biological sources, such as mollusc shells or coralline algae. Sediments settle in different densities and structures, depending on the local wave action and weather, creating different textures, colors and gradients or layers of material.
Coastal erosion is the loss or displacement of land, or the long-term removal of sediment and rocks along the coastline due to the action of waves, currents, tides, wind-driven water, waterborne ice, or other impacts of storms. The landward retreat of the shoreline can be measured and described over a temporal scale of tides, seasons, and other short-term cyclic processes. Coastal erosion may be caused by hydraulic action, abrasion, impact and corrosion by wind and water, and other forces, natural or unnatural.
Barrier islands are a coastal landform, a type of dune system and sand island, where an area of sand has been formed by wave and tidal action parallel to the mainland coast. They usually occur in chains, consisting of anything from a few islands to more than a dozen. They are subject to change during storms and other action, but absorb energy and protect the coastlines and create areas of protected waters where wetlands may flourish. A barrier chain may extend for hundreds of kilometers, with islands periodically separated by tidal inlets. The largest barrier island in the world is Padre Island of Texas, United States, at 113 miles (182 km) long. Sometimes an important inlet may close permanently, transforming an island into a peninsula, thus creating a barrier peninsula, often including a beach, barrier beach. Though many are long and narrow, the length and width of barriers and overall morphology of barrier coasts are related to parameters including tidal range, wave energy, sediment supply, sea-level trends, and basement controls. The amount of vegetation on the barrier has a large impact on the height and evolution of the island.
The Oregon Coast is a coastal region of the U.S. state of Oregon. It is bordered by the Pacific Ocean to its west and the Oregon Coast Range to the east, and stretches approximately 362 miles (583 km) from the California state border in the south to the Columbia River in the north. The region is not a specific geological, environmental, or political entity, and includes the Columbia River Estuary.
A storm surge, storm flood, tidal surge, or storm tide is a coastal flood or tsunami-like phenomenon of rising water commonly associated with low-pressure weather systems, such as cyclones. It is measured as the rise in water level above the normal tidal level, and does not include waves.
Rogue waves are unusually large, unpredictable, and suddenly appearing surface waves that can be extremely dangerous to ships and isolated structures such as lighthouses. They are distinct from tsunamis, which are often almost unnoticeable in deep waters and are caused by the displacement of water due to other phenomena. A rogue wave at the shore is sometimes called a sneaker wave.
Beach nourishment describes a process by which sediment, usually sand, lost through longshore drift or erosion is replaced from other sources. A wider beach can reduce storm damage to coastal structures by dissipating energy across the surf zone, protecting upland structures and infrastructure from storm surges, tsunamis and unusually high tides. Beach nourishment is typically part of a larger integrated coastal zone management aimed at coastal defense. Nourishment is typically a repetitive process since it does not remove the physical forces that cause erosion but simply mitigates their effects.
On 26 December 2004, at 07:58:53 local time (UTC+7), a major earthquake with a magnitude of 9.1–9.3 Mw struck with an epicentre off the west coast of northern Sumatra, Indonesia. The undersea megathrust earthquake, known by the scientific community as the Sumatra–Andaman earthquake, was caused by a rupture along the fault between the Burma Plate and the Indian Plate, and reached a Mercalli intensity up to IX in some areas.
Anglesea is a town in Victoria, Australia. It is located on the Great Ocean Road in the Surf Coast Shire local government area. In the 2016 census, Anglesea had a population of 2,545 people.
Rock fishing is fishing from rocky outcrops into the sea. It is a popular pastime in Australia and New Zealand. It can be dangerous and many people have died. This may improve as more people who are rock fishing are beginning to wear life jackets.
G-Land, also known as Plengkung Beach, is an internationally renowned surf break on Grajagan Bay, Banyuwangi, Alas Purwo National Park, East Java, Indonesia, about half a day by road from the popular tourist destinations of Bali. It is most commonly reached via boat charter from Bali.
A meteotsunami or meteorological tsunami is a tsunami-like sea wave of meteorological origin. Meteotsunamis are generated when rapid changes in barometric pressure cause the displacement of a body of water. In contrast to "ordinary" impulse-type tsunami sources, a traveling atmospheric disturbance normally interacts with the ocean over a limited period of time. Tsunamis and meteotsunamis are otherwise similar enough that it can be difficult to distinguish one from the other, as in cases where there is a tsunami wave but there are no records of an earthquake, landslide, or volcanic eruption. Meteotsunamis, rather, are triggered due to extreme weather events including severe thunderstorms, squalls and storm fronts; all of which can quickly change atmospheric pressure. Meteotsunamis typically occur when severe weather is moving at the same speed and direction of the local wave action towards the coastline. The size of the wave is enhanced by coastal features such as shallow continental shelves, bays and inlets.
In fluid dynamics and nautical terminology, a breaking wave or breaker is a wave with enough energy to "break" at its peak, reaching a critical level at which linear energy transforms into wave turbulence energy with a distinct forward curve. At this point, simple physical models that describe wave dynamics often become invalid, particularly those that assume linear behaviour.
A surge channel is a narrow inlet, usually on a rocky shoreline, and is formed by differential erosion of those rocks by coastal wave action. As waves strike the shore, water fills the channel, and drains out again as the waves retreat. The narrow confines of the channel create powerful currents that reverse themselves rapidly as the water level rises and falls, and cause violent hydrodynamic mixing. However, there is relatively little exchange of water between channels; experimental studies and mathematical modelling of the coastline near Hopkins Marine Station in California have shown that water is rapidly mixed within each channel, but that it mostly moves in an oscillatory manner. Surge channels have been likened to 'containment vessels', retaining water borne gametes and probably enhancing the effectiveness of external fertilisation of marine species dwelling within them.
Hurricane Gabrielle was a powerful tropical cyclone that caused nine fatalities in the United States and Canada, despite remaining hundreds of miles offshore. The tenth tropical cyclone, seventh named storm, fifth hurricane, and first major hurricane of the 1989 Atlantic hurricane season, Gabrielle developed on August 30 from a tropical wave near the west coast of Africa. Under favorable conditions, the depression intensified and became Tropical Storm Gabrielle early on the following day. Rapid strengthening occurred thereafter, with Gabrielle reaching hurricane intensity early on September 1. After becoming a hurricane, further intensification was steady, though by September 5, Gabrielle peaked as a moderate Category 4 hurricane. On the following day, Gabrielle began to slowly level-off in intensity, while gradually curving northward. After weakening to a Category 2 hurricane, the storm passed east of Bermuda on September 8.
Beach evolution occurs at the shoreline where sea, lake or river water is eroding the land. Beaches exist where sand accumulated from centuries-old, recurrent processes that erode rocky and sedimentary material into sand deposits. River deltas deposit silt from upriver, accreting at the river's outlet to extend lake or ocean shorelines. Catastrophic events such as tsunamis, hurricanes, and storm surges accelerate beach erosion.
