A flashover is a cataclysmic escalation of fire in a confined space. It is caused when heat radiating down from the ceiling ignites not only the combustible material below, but also the airborne gasses released by that material. As the name suggests, it can happen in flash, and its results can be catastrophic for interior firefighters. On three successive Saturdays in April, firefighters from Cranberry, Adams, Evans City, Callery and Harmony will use a simulator in Cranberry’s Public Safety Training Center to prepare for the eventuality of a flashover fire. Training will extend from 8:00 AM to 5:00 PM on each day, April 13, 20 and 27. Part of the instruction will be in the classroom, the remainder as hands-on fire training. Successful participants will receive state certification.