Forest fires and wild fires are a major issue, especially in the summer months. The fires have the potential to burn thousands of acres and destroy many millions of dollars worth of property. These fires can become huge news items when they become very large and the fire is out of control (not contained). The weather that promotes a high fire danger is the combination of 4 factors. These factors include dry soil/vegetation, a low relative humidity, a hot temperature and strong wind. Dry vegetation will catch on fire and burn much faster than moist vegetation. Dry vegetation increases the chance a fire will get out of control once it spreads. Low relative humidity aids in the drying of vegetation. Low relative humidity is caused by sunny weather, warm temperatures, a lack of precipitation over several days, wind from a dry source, and sinking air (promotes drying and warming). Hot temperatures promote drying of the surface. The rate of evaporation increases as temperature increases thus hot weather promotes a rapid drying of vegetation, especially excessive and dead vegetation. Strong wind helps spread the fire rapidly. It is much easier to get a fire under control when the wind is calm or weak. This makes it easier to contain the fire. When the winds are strong then hot embers will be blown downwind and spread the fire rapidly. The greatest destruction and spreading from a fire often occurs when the wind is strong. During periods of dry, hot windy weather then it becomes likely that there will be a high fire danger. During these times it is important to not throw a lit cigarette into vegetation and to not leave a camp fire unattended. These are two major causes of fires. Two other causes of fires include lightning strikes and arson. |