Wildland Firefighting Practice Exam

When does the relative humidity descending below a specific percentage start to create favorable conditions for wildland fire?

1. 50%

2. 40%

3. 30%

4. 20%

The correct answer is: 30%

Relative humidity plays a crucial role in the behavior of wildland fires. As it decreases, the moisture content in the vegetation and the fuel available for a fire also decreases, making it easier for ignition and rapid fire spread to occur. When relative humidity falls below 30%, the conditions are often considered particularly favorable for wildland fire activity. At this level, fuels can easily lose moisture, leading to a higher likelihood of ignition and increased fire intensity. Firefighters and fire management teams closely monitor relative humidity as part of their risk assessment. When the humidity drops below this threshold, they may take precautionary measures, such as implementing burn bans or increasing staffing levels for fire response, because the environment becomes much more conducive to fire development and behavior can become unpredictable and aggressive. While percentages above 30%, such as 40% or 50%, can still help mitigate fire risk by retaining moisture in fuels, they do not indicate the same heightened risk associated with levels below 30%. Understanding this threshold is important for wildfire preparedness and response strategies.