In August 2014, a massive landslide struck Jure Village in Nepal, blocking the Sunkoshi River and creating a lake with a volume of 8 million cubic meters. After 37 days, the landslide dam breached causing widespread damage to infrastructure. This research assesses the current likelihood of damming the Sunkoshi River due to Jure landslide and evaluates the effectiveness of a newly constructed debris flow channel system, using Rapid Mass Movement Simulation (RAMMS). Additionally, flash flood modeling is conducted with the HEC-RAS (U.S. Army Corps of Engineers River Analysis System) model. Geomorphic indicators, such as the Morphological Obstruction Index (MOI) and the Hydro-morphological Dam Stability Index (HDSI), calculated at 5.18 and 4.65, respectively, suggest a high probability of damming of the Sunkoshi River due to the landslide, resulting in an unstable dam. Observations along the Khadichaur-Barabise road section reveal simulated flow heights ranging from 3 to 23 m, indicating that the 2- to 3-meter-high barrier wall of the debris flow channel, as measured in the field, is ineffective for debris accumulation. The cracked surface of the barrier walls along with excess debris on the road surface further highlights the inadequacies of the debris flow channels’ dimensions. Friction parameters are scrutinized for their sensitivity to flow velocity, with results indicating that the turbulence coefficient is more responsive than the friction coefficient, having a sensitivity index of 0.338. Flood inundation and hazard maps are generated using HEC-RAS. Improved design and construction of debris flow mitigation structures are essential to manage future risks.