Although the U.S. Forest Service fought wildfires long before World War II, the war brought a new importance and urgency to the effort. At the time, many experienced firefighters and other able-bodied men were serving in the armed forces, leaving fewer at home to fight forest fires. The Forest Service began using colorful posters to educate Americans about the dangers of forest fires in the hope that local communities could prevent them from starting in the first place. Careless citizens were not the only fire threat though, as the Empire of Japan considered wildfires a possible weapon. During the spring of 1942, Japanese submarines surfaced near the coast of Santa Barbara, California, and fired shells that exploded on an oil field very close to Los Padres National Forest. U.S. planners hoped that if Americans knew how wildfires would harm the war effort, they would work with the Forest Service to eliminate the threat. The Japanese military renewed their wildfire strategy later in the war, launching some 9,000 fire balloons into the jet stream, with an estimated 11% reaching the U.S. between November 1944 and April 1945. In the end the balloon bombs caused a total of six fatalities: the wife of Archie E. Mitchell, Elsie, and five children were killed by one near Bly, Oregon, on May 5, 1945. A memorial was erected at what since has been named the Mitchell Monument Historic Site.