California Wildfire Perimeters Since 1878

California's FRAP program maintains a historical GIS dataset of wildland fire perimeters across public and private lands, updated annually with data from the previous fire season. The collection includes fires back to 1878, with current collection criteria based on acreage and impact thresholds. This dataset represents the most complete digital record of fire perimeters in the state, though it is known to be incomplete.

Use Cases

• Analyze fire perimeter size and frequency trends over time using the dataset's temporal coverage back to 1878.
• Model wildfire risk by correlating historical fire perimeters with land cover types like timber, brush, and grass, as referenced in the collection criteria.
• Assess the impact of fires on structures by examining perimeters that meet the threshold of ≥3 impacted residential or commercial structures.
• Compare fire history between agencies by identifying perimeters submitted by CAL FIRE versus other cooperating agencies like the US Forest Service.

Strengths

• Temporal coverage extends back to 1878, providing a long-term historical perspective.
• Data is updated annually in the spring with perimeters from the previous fire season, ensuring regular additions.
• Developed through cooperation of multiple authoritative agencies including CAL FIRE, US Forest Service, BLM, and National Park Service.

Limitations

• The dataset is incomplete, with missing perimeters due to lost records, small fire size below cutoffs, or delayed incorporation.
• Contains known errors such as duplicate fire records and over-generalization of perimeters, which can misrepresent unburned areas.
• Collection criteria vary by agency and land type (e.g., ≥10 acres in timber, ≥50 in brush), potentially creating inconsistencies in coverage.

Provenance

Source

California Department of Forestry and Fire Protection's Fire and Resource Assessment Program (FRAP), with cooperating federal and state agencies.

Collection Method

GIS data developed and maintained annually from submissions by CAL FIRE and cooperating agencies based on defined acreage and impact criteria.

Time Range

1878 to present, with annual updates.

Freshness

Updated annually in the spring.

Geography

Public and private lands within the state of California.