Dense granular flows down inclines remain challenging to understand, but recent advances in techniques and approaches have improved predictions. Three main difficulties arise: (1) energy dissipation in granular flows limits agitation regions, leading to correlated particle interactions; (2) understanding of flows over various boundaries, including flat and erodible bases, has advanced; and (3) microscopic interactions at grain contacts determine dissipation rates, requiring better contact models. An inertial number, derived from shear rate and normal stress, suggests a universal rheology for granular flows. While this approach has succeeded in some cases, it has limitations, such as in accelerating flows or flows down flat walls, which exhibit complex behaviors like thin basal layers and multiple regimes. Michel Louge, a professor at Cornell University, has contributed to research on granular flows, including combustion, fluidized beds, and snow avalanches. His work highlights the complexity of dense granular flows and the need for further theoretical and experimental studies to improve predictive models.Dense granular flows down inclines remain challenging to understand, but recent advances in techniques and approaches have improved predictions. Three main difficulties arise: (1) energy dissipation in granular flows limits agitation regions, leading to correlated particle interactions; (2) understanding of flows over various boundaries, including flat and erodible bases, has advanced; and (3) microscopic interactions at grain contacts determine dissipation rates, requiring better contact models. An inertial number, derived from shear rate and normal stress, suggests a universal rheology for granular flows. While this approach has succeeded in some cases, it has limitations, such as in accelerating flows or flows down flat walls, which exhibit complex behaviors like thin basal layers and multiple regimes. Michel Louge, a professor at Cornell University, has contributed to research on granular flows, including combustion, fluidized beds, and snow avalanches. His work highlights the complexity of dense granular flows and the need for further theoretical and experimental studies to improve predictive models.