Quantifying Post‐Fire Aeolian Sediment Flux Dynamics Following the 2024 Smokehouse Creek Fire: The Role of Wind Seasonality, Thermal Clay Mineral Degradation, and Surface Armoring

Abstract Fire in drylands is commonly associated with enhanced aeolian erosion due to the abrupt loss of vegetation cover. However, the relative contributions of fire‐induced mineralogical degradation of soils, seasonal wind forcing and surface armoring to post‐fire wind erosion remain poorly constrained. This study examines these controls following the largest wildfire on record in Texas' history. Time‐resolved measurements of horizontal sediment flux were collected over 8 months at five burned sites spanning contrasting grazing histories. These data are combined with mineralogical and physicochemical analyses of surface (burned) and subsurface (unburned) soils, as well as X‐ray diffraction characterization of wind‐eroded sediment collected during the peak post‐fire erosion interval. Wind erosion rates were highest immediately after the fire and declined over time, with the seasonal reduction in erosive wind frequency. Two burned sites with relatively low pre‐fire clay mineral content showed erosion fluxes comparable to the control site, suggesting post‐fire surface armoring following deflation of fine particles. Surface soils at high‐flux sites exhibited extensive thermal modification and depletion of illite‐smectite relative to underlying horizons, with losses of the smectite component up to 96% at severely affected sites, with peak surface temperature in 450–700°C range. XRD modal mineralogy of eroded sediments shows dominance of quartz and feldspar and a near absence of clay minerals, contrasting with smectite bearing assemblages at the control site. These results demonstrate that post‐fire aeolian erosion is governed by the pre‐fire clay content available for pyrogenic degradation with wind seasonality and surface armoring controlling the temporal trajectory of aeolian fluxes.