Hurricane Helene (2024) — Wind Damage + Track

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 — catastrophic inland flooding (WNC/Asheville) is 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 − λ_ds) / ζ] for each damage state (Slight → Complete).
4. Mean Damage Ratio = Σ P(ds_i) × CDFactor_i 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)

Event Parameters

References