OTTAWA — In the wake of a recent spate of fires, the Ottawa Fire Department advises that you should be especially careful to prevent fire during the winter. Winter tends to be especially fire-prone, assistant fire chief Richard Oglesby said. The recent fires have all been winter-related, either malfunctioning furnaces or property owners using a variety of heating devices to thaw water pipes or warm up items. Homeowners should make sure their smoke detectors and carbon monoxide detectors are in good working order, he said.