The stairs, walls, floors, doors, and roof were all made of wood. The floors were regularly coated with flammable petroleum based waxes. There were no fire-safe stairwells or doors from the stairs to the second floor. The only fire extinguishers in the school were in the north wing, and they were located 7 feet from the floor, too high for any of the students and most of the adults to reach. The only fire escape was located so that you had to pass through the main hallway which became filled with smoke and gas. The classrooms all had 12 foot ceilings, making the second floor windows 25 feet off the ground, which made jumping a near impossible idea. The scenario for a disaster was set.
The fire was started in the basement of the school in a cardboard trash can at the bottom of the northeast stairwell sometime between 2:00 and 2:30. The fire was burning for 30 minutes before anyone noticed. It slowly filled the staircase with gas and smoke. Because of the high temperatures, a window at the bottom of the stairs shattered, giving the fire a new source or oxygen and causing it to burn out of control. The stairway itself burst into flames and created a chimney-like affect. It sent fire, smoke, and gases up to the second floor. The first floor was effectively blocked by heavy wooden doors. However, the second floor and no doors, and the fire quickly spread through all of the second floor halls. A set of pipes running from the basement to above the second floor ceiling gave the fire a direct route to the attic. It was almost as if the fire had an attack plan as it consumed the second floor north wing, and flew through the loft above the classrooms. By the time that the teachers and students realized that the school was on fire, their only escape in the center hallway was completely ablaze. For the 329 students and 5 nuns on the second floor, the only way left to escape was to jump to the concrete and rock below the windows.