Jersey City, N.J. — Catastrophic wildfires cause extensive damage to property and significant disruption to the lives of property owners. In 2005, more than 8.5 million acres burned, nearly twice the 10-year average. This is according to ISO, a provider of products and services that help insurers measure, manage and reduce risk.
With more people living closer to brushfire areas, which also happen to be preserves of privacy, the exposure has nearly doubled for insurers between 1970 and 2000.
From 1990 through 2003, property losses from catastrophic wildland fire exceeded $6.3 billion, states ISO. The costliest event was the 1991 Oakland Hills, Calif., fire that caused property damage of $2.4 billion in inflation-adjusted 2005 dollars. The insured losses from two wildfires in San Diego and San Bernardino Counties in 2003 amounted to $2.2 billion.
Lightning is the most common cause of wildland fires, which ISO claims cause nearly 80% of remote wildland fires in the United States. But fires are also started, directly or indirectly, by people from cigarettes, campfires, arced power lines, arson and other means. Wildland fires spread in areas that include dense, dry brush (the fuel) and very dry weather. Areas exposed to high wind are particularly vulnerable, and remote locations with poor roads make firefighting difficult.
The combination of wind, temperature and humidity in the burn zone exacerbate wildfires. Strong winds push flames and burning embers toward new fuel sources. Blowing wind can also serve as a fuel drying source in moist areas.
The topography of a landscape–its elevation, direction and steepness of slope, and exposure to sunlight–also affects the spread of wildland fire. Certain fuels grow better under different conditions; and the amount of shade or sunlight, the temperature of an area, and moisture received by an area all determine the type of fuel available for wildland fires.
Many insurers are handling this exposure with sophisticated geographic information systems (GIS) such as ISO’s FireLine, according to ISO. ISO’s tool focuses on three key wildfire risk factors–fuel, slope and road access–to assess the overall hazard rating for each property, down to the street address.
FireLine relies on technology, originally developed by NASA scientists, to better manage their wildfire exposures and educate home owners and businesses on brushfire hazards. It uses a combination of digital elevation models, detailed satellite images and street maps, enabling insurers to better pinpoint a property’s exposure to wildfire hazard.
In 2003, when wildfires raged through a large swath of California, FireLine was able to classify nearly 98% of the geographic area burned as fuels, according to ISO. The system also identified nearly 96% of the residential and commercial properties affected by the fires in San Diego and San Bernardino Counties as being exposed to the wildfire hazard. Virtually all affected properties (99%) were within 2,500 feet of areas that FireLine had identified as heavy or medium fuels.