Some younger students who managed to secure a spot at a window were then unable to climb over the high window sills, or were pulled back by others frantically trying to scramble out. The temperature continued to increase until a flashover occurred in the hallway and several of the classrooms at approximately 2:55 p.m. Firemen struggled desperately to pull students and nuns from windows as those classrooms partially filled with screaming children exploded. Firemen noticed that the white shirts of children in the windows changed color and turned brown.