Fire is an uncontrollable process of burning which causes material damage and endangered material assets and the lives of people and animals. The fire in the open space is the fire that is caused by a human by setting a fire on an open space which got out of control. When talking about the fire in the open space, heat emission and other factors which are typical for the fire can endanger immediate surroundings on a distance bigger than 100 m. In the zone of fire there is smoke, but also other harmful, explosive and toxic gases and substances that can endanger human lives. For the last few decades there has been a significant increase in open fire. This is also noticeable in Croatia, especially in the karst area.