Mount Waialeale is a

shield volcano A shield volcano is a type of volcano named for its low profile, resembling a warrior's shield lying on the ground. It is formed by the eruption of highly fluid (low viscosity) lava, which travels farther and forms thinner flows than the more v ...

and the second highest point on the island of

Kauai Kauai, () anglicized as Kauai ( ), is geologically the second-oldest of the main Hawaiian Islands (after Niʻihau). With an area of 562.3 square miles (1,456.4 km2), it is the fourth-largest of these islands and the 21st largest island ...

in the

Hawaiian Islands The Hawaiian Islands ( haw, Nā Mokupuni o Hawai‘i) are an archipelago of eight major islands, several atolls, and numerous smaller islets in the North Pacific Ocean, extending some from the island of Hawaii in the south to northernmost Kur ...

. Its name literally means "rippling water" or "overflowing water" The mountain, at an elevation of , averages more than of rain a year since 1912, with a record in 1982; its summit is one of the rainiest spots on earth. However, recent reports mention that over the period 1978–2007 the wettest spot in Hawaii is Big Bog on

Maui The island of Maui (; Hawaiian: ) is the second-largest of the islands of the state of Hawaii at 727.2 square miles (1,883 km2) and is the 17th largest island in the United States. Maui is the largest of Maui County's four islands, which ...

( per year).

Climate

Climate and rainfall statistics

The summit of Waialeale features a

tropical rainforest climate A tropical rainforest climate, humid tropical climate or equatorial climate is a tropical climate sub-type usually found within 10 to 15 degrees latitude of the equator. There are some other areas at higher latitudes, such as the coast of southea ...

(

Köppen Köppen is a German surname. Notable people with the surname include: * Bernd Köppen (born 1951), German pianist and composer * Carl Köppen (1833-1907), German military advisor in Meiji era Japan * Edlef Köppen (1893–1939), German author and ...

''Af''), with substantial rainfall throughout the course of the year. quotes per year figure as being the 1912–45 average, an average that quite possibly will have changed since then, while The

National Climatic Data Center The United States National Climatic Data Center (NCDC), previously known as the National Weather Records Center (NWRC), in Asheville, North Carolina, was the world's largest active archive of weather data. Starting as a tabulation unit in New Orl ...

quotes this figure as a 30-year average. The

Weather Network The Weather Network (TWN) is a Canadian English-language weather information specialty channel A specialty channel (also known in the United States as a cable channel or cable network) can be a commercial broadcasting or non-commercial televis ...

and ''The Guinness Book of Weather Records'' quotes rain per year, while quotes as the average annual rainfall at Mount Waialeale and claims falls here. Similarly,

The Weather Network The Weather Network (TWN) is a Television in Canada, Canadian English language, English-language weather information specialty channel available in Canada, the United States and the United Kingdom. It delivers weather information on television, ...

and the ''Guinness Book of Weather Records'' quote 335 days with rain here while suggests that rain falls on 360 days per year. The local tourist industry of Kauai has promoted it as one of the wettest places on earth, which it is. The rainfall at Waiʻaleʻale is evenly distributed through the year.

Causes

Several factors give the summit of Waialeale more potential to create precipitation than the rest of the island chain: # Its northern position relative to the main Hawaiian Islands provides more exposure to frontal systems that bring rain during the winter. # Its peak lies just below the so-called

trade wind The trade winds or easterlies are the permanent east-to-west prevailing winds that flow in the Earth's equatorial region. The trade winds blow mainly from the northeast in the Northern Hemisphere and from the southeast in the Southern Hemisph ...

inversion layer of , above which trade-wind-produced clouds cannot rise. # The summit plateau is flanked by steep walled valleys over deep on the three sides most consistently exposed to moisture bearing weather systems. These serve to funnel and concentrate any available precipitable water directly towards the mountain. # The steep cliffs of the mountain's flanks generate intense orthographic lift, causing the moisture-laden air to rise rapidly – over in less than – This combined with the 'barrier' of the trade-wind inversion, serves to very efficiently squeeze almost all of the moisture out of the incoming clouds directly over and immediately downwind of the peak.

Ecology

The great rainfall in the area produces the

Alakai Wilderness Preserve ''HST-2'', formerly named USNS ''Puerto Rico'' and ''Alakai'', is a vessel owned by the United States Navy Military Sealift Command. She was originally Hawaii Superferry's first high-speed ferry. The vessel was later chartered by Bay Ferries ...

, a large

boggy A bog or bogland is a wetland that accumulates peat as a deposit of dead plant materials often mosses, typically sphagnum moss. It is one of the four main types of wetlands. Other names for bogs include mire, mosses, quagmire, and muskeg; a ...

area that is home to many rare plants. The ground is so wet that although trails exist, access by foot to the Waiʻaleʻale area is extremely difficult. A number of rare local plant species are named for this mountain, including ''

Astelia waialealae ''Astelia waialealae'' is a rare species of plant in the Asteliaceae family that is endemic to the island of Kauai of the state of Hawaii in United States. It inhabits montane bogs within the vicinity of the Alakai Swamp on the island's centra ...

'', ''

Melicope waialealae ''Melicope waialealae'' is a species of flowering plant in the family Rutaceae. It is commonly known as Alani wai. It is endemic to the island of Kauai in Hawaii Hawaii ( ; haw, Hawaii or ) is a state in the Western United States, ...

'', and the

endemic Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found elsew ...

Dubautia waialealae ''Dubautia waialealae'' is a rare species of flowering plant in the family Asteraceae known by the common name Wai'ale'ale dubautia. Like other ''Dubautia'' this plant is called ''na`ena`e''.USFWSSpecies Reports: Listed Plants./ref> Distribution ...

''.USFWS
Determination of endangered status for 48 species on Kauai and designation of critical habitat; Final rule.
''Federal Register'' April 13, 2010.

References

Sources

* * * * * *

External links

Honolulu Star-Bulletin article on Waialeale

Site with hiking info on routes to Waialeale and Kawaikini and summit photos.

"Real-time" rainfall data from the USGS Waialeale Raingauge
{{DEFAULTSORT:Waialeale Landforms of Kauai Mountains of Hawaii Volcanoes of Hawaii Weather extremes of Earth Polygenetic shield volcanoes