<p>Catastrophic debris flows often follow wildfire, and yet the deciphering of fire impact and the debris flow potential over time after a fire is deficient. We exploit a multidata-based framework to quantify the changes in characteristics, triggering rainfall, and initiation mechanisms for debris flows in the Yaoyao catchment burned on April 10, 2021, in western Sichuan, China. Results indicate that wildfires increase the likelihood of both runoff-initiated and landslide-initiated debris flows. During the runoff-dominated phase of the initial rainfall event, volumes of debris flow decreased primarily due to fine source material exhaustion. Subsequently, volume increased as the mode transitioned from runoff-initiated to landslide-initiated processes originating from channel banks. Ultimately, debris flow volumes experienced another decline attributed to post-fire recovery. The latter mode dominated the following debris flow in post-fire years 1 to 3 after the runoff mechanism. Grain coarsening was observed in the debris flow deposits over time following the fire, with the median grain size appearing to be constrained by the bedrock type in the burned areas. The 1-h rainfall intensity varies from 6.84 mm/h of event one to 13.56 mm/h of event seven by post-fire year 3. Satellite-based observations further quantitatively revealed the transition from runoff-generated to the landslide-generated mechanism of post-fire debris flow. Results improve our capacity to retrieve the variation in post-fire debris flow characteristics over time and highlight how the fire promotes the debris flow occurrence.</p>