We had one already this year. Our chief was first on the scene and he could see smoke coming out of the eaves of the house and the occupants throwing their belongings out of an upstairs window. The fire had spread into the walls of the house and caused considerable damage before it was stopped.
Many Charlestown residents burn wood for part of the heat in their homes. That can save a lot of money compared to oil or propane. But creosote forms on the walls of the chimney over time. Enough of a coating can catch fire from the heat of the stove or fireplace and the creosote will burn very hot, enough to crack a brick or stone chimney if it's not already cracked and then the heat and fire can escape into the walls or attic of the house. Many older stone or brick chimneys already have cracks; they are time bombs waiting to go off, and they will take your house with it.
You should inspect your chimney at least a couple times during the heating season, more often if you burn soft wood like pine. The Family Handy magazine has an excellent article about inspecting your chimney here.
If you are adventurous and buy some equipment you may be able to clean your chimney yourself. Two reasonably good articles are here and here.
Most people prefer to bring in a pro. If you use that old fashioned thing called a "phone book" the Yellow Pages has a section for Chimney Cleaning. Or you can look at an online listing here. A big advantage of using a certified chimney sweep is that he or she will know how to inspect your chimney for the cracks and other damage that can be deadly.
by Tom Ferrio