The Kaū Desert is a leeward

desert A desert is a landscape where little precipitation occurs and, consequently, living conditions create unique biomes and ecosystems. The lack of vegetation exposes the unprotected surface of the ground to denudation. About one-third of the la ...

in the district of Kaū, the southernmost district on the Big Island of

Hawaii Hawaii ( ; ) is an island U.S. state, state of the United States, in the Pacific Ocean about southwest of the U.S. mainland. One of the two Non-contiguous United States, non-contiguous U.S. states (along with Alaska), it is the only sta ...

, and is made up mostly of dried lava remnants,

volcanic ash Volcanic ash consists of fragments of rock, mineral crystals, and volcanic glass, produced during volcanic eruptions and measuring less than 2 mm (0.079 inches) in diameter. The term volcanic ash is also often loosely used to r ...

, sand and gravel. The desert covers an area of the Kīlauea

Volcano A volcano is commonly defined as a vent or fissure in the crust of a planetary-mass object, such as Earth, that allows hot lava, volcanic ash, and gases to escape from a magma chamber below the surface. On Earth, volcanoes are most oft ...

along the Southwest rift zone. The area lacks any vegetation, mainly due to

acid rain Acid rain is rain or any other form of Precipitation (meteorology), precipitation that is unusually acidic, meaning that it has elevated levels of hydrogen ions (low pH). Most water, including drinking water, has a neutral pH that exists b ...

fall.

Climate

Kaū desert is not a true desert in that rainfall exceeds per year. However, rain combines with

sulfur dioxide Sulfur dioxide (IUPAC-recommended spelling) or sulphur dioxide (traditional Commonwealth English) is the chemical compound with the formula . It is a colorless gas with a pungent smell that is responsible for the odor of burnt matches. It is r ...

, released by volcanic vents, and forms

. The pH level of the rain, as low as 3.4 during an eruption, inhibits plant growth. Furthermore, water evaporates quickly on the ground and the

tephra Tephra is fragmental material produced by a Volcano, volcanic eruption regardless of composition, fragment size, or emplacement mechanism. Volcanologists also refer to airborne fragments as pyroclasts. Once clasts have fallen to the ground, ...

soil is extremely permeable.

Visiting

The Kaū Desert is popular for walking and hiking tours during inactive periods. It can be reached by following Highway 11 counterclockwise from Kona to the volcano. The trailhead is on Crater Rim Drive, coordinates . By traversing the desert, one can cross the Great Crack and the Southwest Rift Zone, a major fault zone that looks like a giant groove in the earth, before reaching Kīlauea

. The area is part of Hawaii Volcanoes National Park, but often is closed during periods of high volcanic activity, due to the potential for poisonous gas blown southwest by the tradewinds from Halemaʻumaʻu.Closed Areas and Advisories
on Hawaii Volcanoes National Park web site

The 1790 eruption

One of the most devastating explosions in Hawaiian history occurred in 1790. The eruption released

, which formed spheres of

known as accretionary lapilli due to the effect of electrostatic forces and moisture. Chief Keōua Kuahuula was traveling then around Kīlauea to Kaū, after battling the dominant chief Kamehameha I. At least 80 Hawaiian warriors suffocated when volcanic ash entered their

lung The lungs are the primary Organ (biology), organs of the respiratory system in many animals, including humans. In mammals and most other tetrapods, two lungs are located near the Vertebral column, backbone on either side of the heart. Their ...

s. The footprints preserved in the ash were supposedly of these warriors. However, recent research indicates a variety of people used this area for hundreds of years.Keonehelelei – the falling sands
''Hawaii Volcanoes National Park Archaeological Inventory of the Footprints Area'', Jadelyn Nakamura, 2003

References

External links

General description of Kaū Desert
{{DEFAULTSORT:Ka'u Desert Geography of Hawaii (island) Deserts of the United States Deserts of Oceania Hawaiʻi Volcanoes National Park Volcanic deserts