The Air Force's humanitarian operations received wide attention during the 1990s, as they will for years to come. They are part of a well-established tradition dating back three-quarters of a century to the early days of military flight. The nation's first airmen recognized early on aviation's potential for alleviating the effects of natural disasters. As early as September 1919, Army Air Service planes from Kelly Field, Texas, dropped food supplies to marooned flood victims along the Rio Grande. On a few occasions during the 1920s, American aviators bombed their own country-for good cause. They delivered ordnance against ice jams in the Delaware, Platte, and Susquehanna rivers to prevent flooding, save bridges, and restore navigation. In March 1929 at least twenty-one airplanes from Maxwell Field, Alabama, delivered twenty-seven tons of food and other supplies to flood victims in the southern part of the state. The Army flew several dramatic relief missions during the 1930s. In 1932 bombers dropped supplies to Navajo Indians who had become snowbound by severe blizzards in Arizona. In December 1935 the 5th Bombardment Group bombed the Mauna Loa volcano, diverting its lava flow away from Hilo, Hawaii. In 1936 Air Corps squadrons flew food and other supplies to flood victims in Pennsylvania and the following year to southern Illinois. During February 1939 the Army air-delivered medical aid in the wake of an earthquake in Chile. World War II proved the most costly conflict in history. It has been estimated that during the six years of warfare, about 85 million people were killed and another 60 million rendered homeless. Around the globe, staggering numbers of unfortunates needed food and medical relief.