Hawai‘i Island

Hawaiʻi Island is unique in that it is the only Hawaiian island with ongoing active volcanic eruptions. However, humans are still by far the leading cause of wildfire ignitions. The majority of wildfires on Hawaiʻi Island are caused by human error or arson, especially near developments, power line right of ways, and along roadsides.

Fire Today

Rainfall follows the typical pattern of the Hawaiian Islands, with more rain along the eastern windward coast. Mauna Kea and Mauna Loa create a rain shadow that results in drier conditions on the western leeward coasts. Most of the former sugar plantation lands are on the wetter windward side of the island, along the Hāmākua Coast. Despite this location, there is a long history of fires in the area. It was the large 1901 Hāmākua coast fire that was the impetus for keeping wildfire records in Hawaiʻi. >> READ MORE

On the leeward side, the Kohala area is particularly fire-prone. This drier region with large areas of fallow pasture and agricultural land has a high rate of ignitions vis-a-vis human infrastructure, as well as more regular large fires.

Fires > 50 Acres 1999-2018, Hawai‘i Island (Credit: UH Wildland Fire)

The growing footprint of these grass-dominated fallow agricultural lands combined with increasing human population increases the risk of wildfire across the island. The hazardous vegetation and high number of ignitions is exacerbated by climate change creating more frequent drought conditions.

Seasonal variation in rainfall also affects both ignitions and the extent of areas which burn. Particularly wet periods over a rainy season can, counterintuitively,  significantly elevate hazard levels. Increased precipitation may lead to a surplus of vegetation growth, becoming potential fuel during subsequent drier periods, thereby elevating the risk of large wildfires. Given the changing wind and rainfall patterns arising from climate change, this may lead to increased risk.

Hawai‘i Island Average Acres and Ignitions (2012-2020)
Hawai‘i Island Average Acres and Ignitions (2012-2020)

Recent Resources For Hawai‘i

Polipoli Fire Demonstrates Vulnerability of Maui ‘Alauahio (‘Elepaio, 2008)

January 1, 2008

Authors Hanna L. Mounce, Fern Duvall and Kirsty J. Swinnerton consider the effects of a massive brush fire in January 2007 on the endangered ‘Alauahio forest bird population in Polipoli including possible effects on foraging, breeding and reproduction.

Assessment of Livestock Grazing Impacts on Fuels and Cultural Resources at Mākua Military Reservation (Warren et al, 2007)

November 1, 2007

The project was developed by US Army Garrison (HI) primarily as a pilot study to assess the use of livestock to manage vegetation growth at Mākua Military Reservation (MMR) on the island of O‘ahu, Hawai‘i. The objective was to determine the feasibility of reducing grass height to a range of 3 to 19 inches, and thereby reduce the threat of catastrophic wildfires on these important training lands as well as adjacent non-military lands.

Effects of Prescribed Grazing and Burning Treatments on Fire Regimes in Alien Grass-dominated Wildland-Urban Interface Areas, Leeward Hawaii (Castillo and McAdams, 2006)

November 7, 2006

This project was designed to evaluate at a practical scale the effectiveness and costs of a range of fine fuels management treatments in West Hawai‘i Island. The study occurred along a major inland highway from which wildfires frequently originate. We applied four major treatments that included a control (no treatment), prescribed burning, cattle grazing, and a combined burning and grazing treatment. Aerially-applied herbicide was then applied to half of each of these primary treatments resulting in a total of eight unique treatment combinations.