Wildfires have many causes including
- lightning
- volcanic eruptions
- human causes (Most common - discarded smoking products, campfires, arson, etc.)
- downed power lines
- sparks from equipment
Much of the reason a thunderstorm can be called dry is due to temperature and humidity below the clouds. It will rain, but the rain (and other forms of precipitation) never reaches the ground. Rain that does not reach the ground is known as virga. Dry thunderstorms can be predicted well in advance of the storm leading officials to warn residents in an area of the possibilities of a wildfire. Incident meteorologists (IMETs) go onto full alert. These specially trained meteorologists look for the fuels that will help a wildfire to spread. IMETs have training in microscale forecasting, fire behavior, and fire operations. They also act as managers who can help to coordinate control efforts. With predictions of wind speed and direction, decisions are made on how to best control and contain wildfires.
The main ingredients for a possible critical fire weather condition are
- hot temperatures,
- low humidity,
- high winds,
- and a dry fuel source such as brush or trees.
