At approximately 11:50 a.m. (Beijing time) on February 8, 2025, a catastrophic landslide, named Junlian landslide, struck Junlian County, China, resulting in ten deaths, two injuries, and 19 missing. Characterized by a high-elevation shear outlet, intense dynamic fragmentation, and an average velocity of 19.3 m/s, this event represents a typical high-mobility rock avalanche. The avalanche covered an area of 1.74 x 105 m2 with a travel distance (L) of 1180 m and a vertical elevation drop (H) of 440 m, yielding a low H/L ratio of 0.37. The initial failure volume (0.37 Mm3) increased to a final deposit volume of 0.6 Mm3 due to a strong entrainment effect, with an amplification factor of 1.62. Two distinct directional shifts during movement created a complex zonation of affected areas: the first shift generated a throwing area, while the second produced a climbing-up area along the path. The dynamic process induced intense fragmentation and entrainment, with the proportion of boulders decreasing exponentially as their size increased (only 1% exceeded 5 m2 in area size). The source area comprised a reverse-dip slope within the lower Triassic Feixianguan formation, characterized by interbedded sandstone and mudstone layers. Densely distributed structural planes dissected the rock mass into unstable wedge-shaped blocks, ultimately leading to wedge toppling failure. This failure mechanism, coupled with tectonic preconditioning of structural weaknesses, underscores the critical role of lithological heterogeneity and structural discontinuities in slope instability.