 Thousands of firefighters fought the fires, assisted by dozens of helicopters and fixed-wing aircraft which were used for water and fire retardant drops.At the peak of the effort, more than 9,000 firefighters were assigned to the park.With fires raging throughout the Greater Yellowstone Ecosystem and other areas in the western United States, the staffing levels of the National Park Service and other land management agencies were inadequate for the situation; more than 4,000 U.S. military personnel were soon brought in to assist in wildfire suppression efforts.