Wildfire Assessments
Evaluate
Evaluating wildfire risk involves a comprehensive assessment of multiple interrelated factors, including hazard, exposure, and vulnerability. Hazard is defined by the likelihood and intensity of a wildfire, where likelihood refers to the annual probability of a fire occurring in a specific location, often derived from fire behavior modeling across thousands of simulations that account for weather, topography, and ignition patterns.
Intensity, which measures the energy expected from a wildfire, is largely influenced by the physical landscape and available fuel, such as vegetation type and terrain slope, and is often expressed in terms of flame length.
Behavior
Evaluating wildfire behavior involves analyzing the complex interactions between fuel, weather, and topography, known as the "Fire Behavior Triangle".
These factors collectively determine how quickly a fire spreads, its intensity, and the direction it travels. Fire spreads through three primary mechanisms: ground fires, which burn slowly beneath the surface; surface fires, which move along the forest floor; and crown fires, which jump between treetops and spread rapidly, posing significant danger.
Risks
Evaluating wildfire risks to communities involves understanding the combination of wildfire hazard and vulnerability. Wildfire hazard is defined by the likelihood and intensity of a fire, while vulnerability is determined by exposure and susceptibility.
Wildfire likelihood refers to the annual probability of a fire burning in a specific location, calculated through fire behavior modeling across thousands of simulations that account for weather, topography, and ignition patterns from recent decades.
This likelihood is averaged across housing units in a community and does not predict current fire danger conditions.
Wildfire intensity, measured in terms of flame length, reflects the energy expected from a fire and is influenced by topography and available vegetation, such as forests on hillsides producing higher intensity than grasslands on flat ground.