Straight-Line Wind (SLW) Vulnerability Model

Per-building wind damage probability computed using Hazus Hurricane Technical Manual v7 lognormal fragility curves for four construction classes. Wind-only component — surge modeled separately in the flood model.

Algorithm

  1. Peak gust observations from IEM ASOS (hourly METARs) and SPC Local Storm Reports (LSR) are merged into a point observation set.
  2. Storm-track-relative wind decay model (exponential decay, λ=80km) assigns peak_gust_mph to each building within the storm corridor.
  3. Hazus lognormal fragility: P(DS ≥ ds | v) = Φ[(ln v − λds) / ζ] for each damage state (Slight → Complete).
  4. Mean Damage Ratio = Σ P(dsi) × CDFactori where CDFactors: Slight=0.02, Moderate=0.10, Extensive=0.50, Complete=1.00.
  5. ground_up_loss = MDR × RCV (footprint_sqft × $150/sqft — full structure).

Fragility Parameters (W1 — Light Wood Frame)

Slight (2%)75 mph median • ζ = 0.35
Moderate (10%)95 mph median • ζ = 0.35
Extensive (50%)115 mph median • ζ = 0.35
Complete (100%)145 mph median • ζ = 0.35

Event Parameters

EventHurricane Ian — Sep 28, 2022
Event type multiplier1.05× (tropical)
Calibration factor0.11 (post-MDR scalar)
Observations303 (ASOS + LSR)
Max observed gust135 mph
NCEI total benchmark~$113B (all perils incl. surge)

References

Hazus Hurricane Technical Manual v7. FEMA/NIBS.
IEM Mesonet. ASOS peak gust archive.
SPC Storm Data. Local Storm Reports (LSR) wind entries.
Buildings colored by wind damage ratio (MDR) — Hazus W1/W2/MH/MLRM fragility • 303 observations • Wind-only (surge modeled separately) • Click a building for full model output
Loading wind damage data…