October 2017 Tubbs Fire — Sonoma/Napa, CA

36,807 acres • 5,643 structures destroyed • Diablo wind event • Mode 1 Damage Assessment

⚠ Uncalibrated — DR multipliers pre-DINS calibration. Loss estimates are indicative only.

Estimated Loss

$2.0B

Ground-up structural loss (Mode 1)

$48.6B total RCV in bbox

Color Mode

Zone Legend

Z1Core (interior)

Z2Transition (0–150m)

Z3Ember cast (downwind)

Z4Fringe (500m–1.5km)

Zone Summary

Zone	Structs	Est. Loss
Z1	3,141	$1,417M
Z2	1,390	$191M
Z3	1,427	$70M
Z4	11,351	$129M

Layers

Fire perimeter LANDFIRE fuel model

Perimeter: NIFC GeoMAC (final, 36,808 ac)
Structures: Hummingbird SI (CA)
Zones: geometric distance from perimeter
DR: pre-calibration fixed values

Mode 1 — Damage Assessment Methodology

Zone Architecture

Structures are assigned to zones Z1–Z5 based on their geometric relationship to the final fire perimeter:

Z1 (Core): Interior of burned perimeter. DR 0.70–0.90. Primary loss zone.
Z2 (Transition): 0–150m outside perimeter. DR 0.20–0.40. Residual/spotting.
Z3 (Ember cast): 150–500m, downwind sector ±60°. DR 0.05–0.15.
Z4 (Fringe): 500m–1.5km. DR 0.01–0.05. High-value structures only.

BDI (Lee Building Damage Index)

BDI = H × V × E, where H is the zone hazard weight, V is vulnerability (roof material, occupancy type, slope), and E is normalized RCV exposure. Loss = DR(BDI) × RCV.

Calibration Status

DR multipliers are pre-calibration defaults. DINS (CAL FIRE structure damage surveys) calibration against Camp Fire and Tubbs Fire will adjust zone-specific DR values. Estimates shown are indicative only.

Perimeter Source

Final containment perimeter from NIFC GeoMAC (36,808 acres). Sequential daily perimeters (26 observations Oct 8–31) available for Event Replay mode (Phase 3).