Fire protection engineers focused on interior fires, and forest fire behavior models ignored how fire moves into buildings. Now, however, researchers and others are responding with models that can assess the risk of structures igniting and databases that track the features common in houses destroyed by wildfire. Research shows that fire intensity is the most important factor affecting whether a structure will ignite. Once the intensity of a wildfire passes a certain point, little else matters. The amount of space cleared of flammable vegetation around structures affects whether fire spreads to structures.
Access affects firefighters' ability to suppress fire and protect structures.
Defensive action can reduce the likelihood of a structure igniting and, in the event it does ignite, can increase the structure's prospects for survival. Fire danger rating systems can now gauge the likelihood that fires will start, and models can predict the spread of fires. Other new tools and technology combine information about fuels, obtained from satellite imagery, with information about roads and topography to generate hazard maps and assess the wildfire risk facing specific properties. The accumulation of fuel and continued development also suggest that insurers will face an increasing stream of claims from smaller but more numerous fires. But the programs those groups have undertaken can be costly and unpopular.