Three Risk Components

The relative risk assessment chart uses three risk components:

• values
• hazard
• probability

Each of these components is assessed independently. Then, the three outputs are evaluated in a final step that provides the relative risk for the fire. Each risk component is defined by three variables. One variable is located on the right and one on the left side of the box and the third variable is defined by three interior lines extending from top to bottom.

Values

Values are those ecologic, social, and economic resources that could be lost or damaged because of a fire. Ecologic values consist of the following:

• vegetation
• wildlife species and their habitat
• air and water quality
• soil productivity
• other ecologic functions

Social effects can include the following:

• life, cultural and historical resources
• natural resources
• artifacts
• sacred sites

Economic values can include the following:

• property and infrastructure
• economically valuable natural and cultural resources
• recreation
• tourism opportunities

Hazards

The hazard in wildland fire is composed of the following:

• Conditions under which the fire occurs and exists;
• Ability of the fire to spread and circulate;
• Intensity and severity the fire may present; and
• Spatial extent of the fire.

Probability

Probability refers to the likelihood of a fire becoming an active event with potential to adversely affect values.

Relative Risk Considerations

• The breakdown of each aspect is not all inclusive and considerations can vary by place and time.
• Users are expected to exercise their judgment in determining the ratings; information is intended to provide both guidance in completion and flexibility in determining exactly what the descriptions mean.
• Local information can and should be amended to the lists to better reflect site-specific situations.
• Local, site-specific information concerning air quality and smoke management must be amended into the Wildland Fire Relative Risk Assessment to reflect variances in situations and local values and regulatory concerns.
• Air-quality criteria should be reflected in the values assessment portion, smoke production can be incorporated into the hazard descriptive list, and descriptive information related to the probability of adverse smoke events, if available, can be addressed as part of the probability assessment.