 The steepness and ruggedness of the terrain in Blackwater Canyon meant firefighters had to access the fire on foot , carrying all their supplies . On the Blackwater fire , pack horses were used to ferry supplies from the access roads to an upper base camp . Many of the firefighters were employed by the Civilian Conservation Corps ( CCC ) and had limited training in wildfire suppression and behavior , as the CCC was mainly engaged in construction projects . After a series of severe and deadly forest fire events in the early 20th century , officials established the 10 am rule in 1935 , which recommended aggressive attack on all fires and to have them controlled by 10 am , the day after they are first detected . This was intended to prevent fires from remaining active into the afternoon when the rising temperatures and more turbulent air caused fires to expand and become more erratic . A scientific publication about fire behavior that could be used for widespread training of firefighters first became available in 1951 . 
