Multi?Stage Soil?Hydraulic Recovery and Limited Ravel Accumulations Following the 2017 Nuns and Tubbs Wildfires in Northern California

Wildfire can impact soil-hydraulic properties by reducing saturated hydraulic conductivity and sorptivity, making recently burned landscapes prone to debris flows flash floods. The post-fire hazard window range from years decades. In Northern California, where wildfire frequency is steadily increasing, the recovery wildfires unknown. Following October 2017 Nuns Tubbs fires in Bay Area of we established 41 monitoring sites for repeat tension-disc infiltrometer measurements field-saturated (Kfs) over 3.5 years. Our site arrays, which encompass grasslands, chaparral, oak conifer forests across a lithology, show marked decrease Kfs following swift partial initial rainy season. time series reveals complex path distinct seasonal stages. Analysis changing Kfs, infiltration model residuals collectively suggests that these stages are related transitions between processes like structural soil sealing rainsplash, thermal cracking bare soil, vegetation regrowth. While rates were strongly impacted fires, dry ravel estimates an order magnitude less similar slopes than 2009 Station fire San Gabriel mountains Southern suggesting limited flux may insufficiently load channels initiate within-channel failure. analysis California experience rapid pathways toward flow initiation.