Property Wildfire Risk and Burn Probability

Start with modeled wildfire hazard

Where coverage is available, the report uses USDA Wildfire Risk to Communities data for annual burn probability and modeled risk to potential structures at the location cell. These values provide nationally consistent screening context, not a prediction that a specific property or structure will burn.

• Burn probability describes modeled annual wildfire likelihood for the mapped location cell.
• Risk to potential structures combines modeled wildfire likelihood, intensity, and generalized consequences.
• The model does not describe current fire danger, recent vegetation change, or property-specific mitigation.

Add community and historical context

FEMA National Risk Index and MTBS answer different supporting questions. NRI adds tract- or county-scale exposure and loss context, while MTBS shows nearby mapped historical burn perimeters and density.

• Community context should not be presented as a parcel measurement.
• Historical burn proximity does not predict where the next fire will occur.
• Missing source coverage is excluded from scoring rather than treated as zero risk.

Understand California Fire Hazard Severity Zones

For California locations, CAL FIRE Fire Hazard Severity Zones can add Moderate, High, or Very High hazard context. TrueViewly uses this as corroborating evidence, not as a nationwide component or insurance determination.

• FHSZ describes long-term fire hazard, not structure vulnerability.
• Responsibility area and severity are shown when the source covers the coordinate.
• Insurance availability and pricing must be discussed with a qualified insurance professional.

Read the housing and vegetation setting (WUI)

SILVIS 2020 Wildland-Urban Interface mapping adds census-block context. Intermix describes housing mixed with wildland vegetation; Interface describes housing near contiguous wildland vegetation. Neither classification is a fuels inspection at the property.

• The prepared WUI source scope covers all 50 states, DC and the five inhabited U.S. territories. A report still depends on available data and a clear mapped match.
• The WUI classification year is 2020. Vegetation fields use 2019 for CONUS, 2016 for Alaska/Hawaii and 2020 for territories; inspect the source year rather than assuming present-day conditions.
• Non-WUI does not rule out nearby fuels or ember exposure. Water, ambiguous boundaries and missing coverage remain distinct from a land non-WUI classification.

Separate conditional intensity from annual fire likelihood

USDA WRC conditional flame length and probabilities of exceeding 4 ft or 8 ft describe modeled intensity if a fire occurs. They are not annual burn probabilities, loss forecasts or measured flame lengths at a building.

• Conditional flame length is shown in feet; exceedance probabilities are percentages given fire, not percentages per year.
• The intensity layers use 30 m cells and 2022 landscape conditions across CONUS, Alaska and Hawaii. They do not cover U.S. territories.
• A valid modeled zero is different from no modeled estimate or an unavailable layer. None establishes property safety.
• WUI and intensity are supporting evidence, not additional score inputs. A lower conditional intensity does not cancel a higher score based on annual risk and other context.

Use the result for targeted follow-up

A higher or uncertain wildfire signal should lead to property-specific questions about fuels, defensible space, construction, access, water supply, evacuation, fire-district capacity, and insurance.

• Inspect vegetation and defensible-space conditions at the property.
• Review roof, vents, decks, attachments, and ember exposure with an appropriate professional.
• Confirm local hazard maps, mitigation requirements, access, and insurance conditions.

Sources and further reading

• USDA Wildfire Risk to Communities methods
• SILVIS 2020 Wildland-Urban Interface

Source publications and live agency pages may differ from the snapshot used in a report. Check the report's source dates and confirm material findings through the responsible authority.