The 1998 Ice Storm in Eastern Ontario produced a large amount of debris from damaged and downed trees. Wood chippers have been used to reduce the debris into more manageable wood chip piles. However, wood chip piles pose a potential fire hazard if not managed correctly. Generally, outdoor wood chip piles contain a high moisture content and are not usually susceptible to surface fire ignition. On the few occasions where surface fires have occurred, it has usually been caused by exposure to another fire or from equipment working on the piles.
Internal fires are much more common than surface fires and are difficult to detect and extinguish.
Such fires are capable of burning for extended periods before any obvious indications of a fire are observed. Spontaneous heating is caused when heat produced by the microbial decay of wood is not readily dissipated. In some piles, the temperatures continue to rise due a number of factors. Fires frequently occur while attempts are made to separate heated from non-heated chips. When heated chips are exposed to sufficient air, combustion may occur.