Which term refers to a narrow canyon that can funnel fire?

• A. Slope
• B. Aspect
• C. Chimney
• D. Saddle

Answer: (C)

A chimney is a narrow canyon that can funnel fire. When flames are funneled through a tight, rocky channel, the walls confine the air flow and heat, speeding up updrafts and accelerating the flame front as it moves uphill. This geometry concentrates heat and embers, making the fire spread much faster than it would on open terrain. The effect is dangerous for crews because it can lead to rapid changes in fire intensity and direction, including wind-driven runups and spotting ahead of the main fire.

Slope describes how steep the terrain is and how fire climbs upslope, but it doesn’t imply a bottleneck that concentrates flow. Aspect is about which direction a slope faces, affecting sun exposure and drying, not channeling fire. A saddle is a low pass between ridges; it can influence fire movement, but it’s not a narrow channel that funnels fire. The funneling behavior specific to a tight canyon is what defines a chimney.