Around 10,000 service members participate in Northern Edge, which lasts from May 13-24. The exercises take place primarily above the Alaska Range and in the Gulf of Alaska. A jet-fighter taking off from Joint Base Elmendorf-Richardson during exercises in 2015. (Photo: Zachariah Hughes – Alaska Public Media) Environmental groups have criticized both the timing and scale of the trainings, which take place as fish and marine mammals are passing through the waters around the state. The military says this time of year provides an abundance of daylight, along with relatively mild weather that is conducive to the large-scale effort. Thousands of military personnel are in Alaska for the start of Northern Edge 2019. The biennial training exercise is the largest in the state, bringing troops, aircraft and ships from all the service branches. Personnel come to Alaska from across the contiguous United States and Pacific. In a press release, the Air Force says around 250 aircraft will take part. And, for the first time in a decade, an aircraft carrier from the Pacific Fleet will be on hand.