The most deadly wildfire in the United States in over a century totally destroyed the historic whaling town of Lahaina on the island of Maui, Hawaii, and resulted in 97 confirmed deaths, with 31 individuals still missing. Hawaiian Electric Company said that power lines falling in high winds seem to have caused a fire during the early morning of 8 August 2003, but power lines in West Maui had been de-energized for more than six hours by the time a second afternoon fire began in the Lahaina area, a possible flare-up of the original blaze that officials thought had been contained. The fire rushed down dry hillsides toward the community of 13,000 that had once served as the capital of the Hawaiian kingdom, and the lack of warning sirens or texts, combined with only one open road through town, forced many to try to ride out the firestorm in the adjacent ocean waters while boats in the harbor burned. The 911 system collapsed and fire hydrants ran dry, leaving Lahaina a collection of charred remains of buildings and cars.
One of the issues that will likely be studied is whether exterior fire sprinkler protection could have stopped the fire, mitigating the huge loss of lives and property. Such systems have been around for more than a century, and have proven successful in many instances. For example, an exterior sprinkler system was installed at the Old Faithful Inn in Yellowstone National Park in 1947, and is credited with saving the historic wooden building from the North Fork fire that engulfed the vicinity of the inn in 1988.
While water supplies needed for exterior protection systems are large, installations in seaside towns like Lahaina could rely upon the same technique traditionally used in sprinkler protection of cruise ships, where a small automatically available fresh water supply can be augmented by saltwater through a sea chest in the event of an emergency. Yet there are also questions regarding the effectiveness of the water systems under high wind conditions. The development of a high pressure system to the north of the island combined with a low pressure hurricane to the south of the island had produced wind gusts exceeding 60 mph (97 kph) at the time of the Lahaina fire.
A number of small companies are now offering the installation of wildfire sprinkler systems in the western United States, while companies in Australia are selling “bushfire sprinkler systems.” Many of these systems are based on the use of lawn-care type rotating sprinklers, and can be manually activated, activated remotely, or activated automatically through the use of ultraviolet detection.
The NFPA, through its “Firewise USA” program aimed at reducing the risk of wildfires, has published a one-page fact sheet entitled “Exterior Sprinkler Systems.” Produced in cooperation with the USDA Forest Service, the US Department of the Interior and the National Association of State Foresters, the fact sheet notes that post-fire assessments have shown exterior sprinkler systems can be effective in helping a home survive a wildfire, but cautions there are still potential issues:
- A water supply is needed for a period that could be up to 8 hours
- The effectiveness of a system is questionable if a neighboring home is burning due to excessive radiant heat and possible contact exposure
- While the systems can be activated manually or by an automated device, the ability of the systems to activate on the basis of ember exposure has not been determined, and embers can be transported for up to a mile from a flame front
- The most threatening wildfires occur during high-wind events, which can affect distribution of water droplets
As a result, the NFPA fact sheet recommends that exterior sprinklers be considered only a supplement to already proven mitigation strategies, including reduction of potential fuels around the home exterior, removal of roof and gutter debris, and use of noncombustible and ignition resistant building materials and designs.
Although the publication suggests that local fire departments may have suggestions to help minimize water consumption when the system is fed from a municipal supply, it does not consider the possibility that homeowners may be prevented from installing systems that would deplete marginal public supplies during a wildfire, especially in rural areas.
Note: A link to satellite images of Banyan Court Park and other areas of Lahaina taken before and after the fire can be found here: