The southeastern Qattara Depression is a geomorphologically active region of Egypt’s Western Desert, where longitudinal dune fields intersect major development corridors, including the New Delta Project and petroleum concessions. This study presents the first integrated multi-temporal assessment of longitudinal dune morphodynamics over 35 years (1990–2025) using satellite imagery, digital elevation data, geological maps, and climatic records. Fifty-two dunes were analyzed using morphometric and kinematic indicators. Simple dunes dominate (78.85%), while complex forms account for 21.15%. Dune volumes range from 6.42 × 10⁶ to 4.98 × 10⁹ m³. Strong correlations between dune dimensions and volume (r = 0.73–0.89), indicate that lateral accretion as the primary growth mechanism. Dune activity has accelerated through increasing lateral migration, longitudinal growth, and vertical accretion driven by high-energy winds and prolonged drought. An Analytic Hierarchy Process (AHP) framework integrated the Sand Mobility Index, Normalized Difference Sand Index, and Normalized Difference Vegetation Index to assess geomorphological hazard and land-use vulnerability. The resulting dune hazard, vulnerability, and sand-drift risk maps spatially classify risk. ROC–AUC validation showed excellent predictive performance (AUC ≈ 0.93). High and very high hazard zones cover 22.96% of the study area, revealing substantial threats to ongoing development.