Mount Waialeale is a

shield volcano A shield volcano is a type of volcano named for its low profile, resembling a 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 viscous lava ...

and the second highest point on the island of

Kauai Kauai (), anglicized as Kauai ( or ), is one of the main Hawaiian Islands. It has an area of 562.3 square miles (1,456.4 km2), making it the fourth-largest of the islands and the 21st-largest island in the United States. Kauai lies 73 m ...

in the

Hawaiian Islands The Hawaiian Islands () are an archipelago of eight major volcanic islands, several atolls, and numerous smaller islets in the Pacific Ocean, North Pacific Ocean, extending some from the Hawaii (island), island of Hawaii in the south to nort ...

. 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 Maui (; Hawaiian language, Hawaiian: ) is the second largest island in the Hawaiian archipelago, at 727.2 square miles (1,883 km2). It is the List of islands of the United States by area, 17th-largest in the United States. Maui is one of ...

( per year).

Climate

Climate and rainfall statistics

The summit of Waialeale features a

tropical rainforest climate A tropical rainforest 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 southeast Florida, United States ...

(

Köppen Köppen is a German surname. Notable people with the surname include: * Bernd Köppen (1951–2014), German pianist and composer * Carl Köppen (1833-1907), German military advisor in Meiji era Japan * Edlef Köppen (1893–1939), German author ...

''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. In 2015, the NCDC merged with two other ...

quotes this figure as a 30-year average. The Weather Network 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 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 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 Hemisphere, ...

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 orographic 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, a large boggy 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'', '' Melicope waialealae'', and the

endemic Endemism is the state of a species being found only 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 foun ...

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

References

Sources

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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