The MC-130 departed Borinquen to fly segments of two low-level routes that are used by the Puerto Rico ANG. After cresting a ridgeline power was reduced and the aircraft began a descent. The crew received an obstacle warning, but the crew believed this was caused by the weather (driving rain and heavy fog) and descent was continued. The Hercules eventually began to climb again until it struck a ridgeline at 2018 feet MSL. PROBABLE CAUSE: “By clear and convincing evidence, the cause of this mishap was an uncharacteristic loss of situational awareness by the entire mishap flight deck crew and the subsequent lack of an appropriate response to obstacle warnings. The Board President further found the following factors substantially contributed to the mishap: overall crew preparation, a misdirected focus on the weather, crew resource management dynamics, and crew judgment as it relates to existing directives.”