Avulsion-triggered channel widening processes in an unvegetated meandering system

The dataset comprises a comprehensive 15-year spatiotemporal record of the unvegetated Sulengguole River, integrating high-resolution satellite imagery, field surveys, and derived morphodynamic metrics to document a complete post-avulsion cascade. High-resolution optical imagery and in-situ photographs visually capture the multi-stage morphological evolution, detailing the 2019 annexational flow capture, subsequent rapid channel widening, and the critical emergence of alternate bars. These visual observations are directly substantiated by extensive quantitative spatial analyses, which track the downstream kinematic propagation of both the channel-widening waves and the critical half-width-to-depth ratio (β) instability fronts. Ultimately, this combination of planform imagery and extracted geometric data explicitly links the macroscopic avulsion-driven reorganization to the extreme, width-dependent acceleration of local meander migration.