Wildland Firefighting Practice Exam

With every 20% increase in slope, the rate of spread of a fire will what?

1. Remain the same

2. Increase by 10%

3. Double

4. Halve

The correct answer is: Double

A 20% increase in slope significantly impacts the rate of spread of a fire due to the principles of fire behavior on sloped terrain. Fire spreads faster uphill than on flat ground because flames become closer to available fuel as the slope increases. The steeper the slope, the more direct heat transfer occurs to adjacent fuels, thus enhancing combustion and accelerating the fire's progress. When discussing a 20% increase in slope leading to a doubling of the rate of spread, this reflects established fire behavior knowledge. Research indicates that for every increase of 10% in slope, the spread rate can increase substantially, often cited as approximately doubling under certain conditions. Therefore, a 20% increase in slope logically aligns with this understanding, indicating an intense interaction between the terrain and fire dynamics. Other options do not capture the significance of topographical features in fire behavior. A constant rate, for instance, ignores the inherent physics of slope influence on fire dynamics. Any minor increase in spread rate, as suggested by a 10% increase, underestimates the compound effects seen in wildfire scenarios. Furthermore, the notion of halving the spread rate does not align with recognized fire behavior theories, which highlight the acceleration due to slope. Thus, the notion of doubling is the