Mount Waialeale

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Waialeale or Rippling Waters, the small lake that is the namesake of Mount Waialeale.

The Waialeale raingage. The fabled wettest known spot on earth.

Mount Waiʻaleʻale (Hawaiian for "rippling waters"), elevation 5,148 ft (1,569 m), is the second highest point on the island of Kauaʻi in the Hawaiian Islands. Averaging more than 460 inches (11,680 mm) of rain over the last 32 years, with a record 683 inches (17,340 mm) in 1982, its summit is considered one of the rainiest spots on earth. It has been promoted in tourist literature for many years as the wettest spot, but 38-year averages at Mawsynram, India records 11,873 mm (467.4 inches) over a period of 39 years. However, Mawsynram's rainfall is concentrated in the monsoon season, while the rain at Waiʻaleʻale is more evenly distributed through the year.

Several factors give the summit of Waiʻaleʻale 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.
It has a relatively round and regular conical shape, exposing all sides of its peak to winds and the moisture that they carry.
Its peak lies just below the so-called trade wind inversion layer of 6,000 feet (1,800 m), above which trade-wide-produced clouds cannot rise.
And most importantly, the steep cliffs cause the moisture-laden air to rise rapidly - over 3,000 ft in less than half a mile - and drop a large portion of its rain in one spot, as opposed to spreading the rain out over a larger area if the slope were more gradual.

The great rainfall in the area produces the Alakaʻi Swamp, 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.