Why is it critical to monitor structures located in chimneys, box canyons, saddles, or on steep slopes during a fire?

Monitoring structures located in areas such as chimneys, box canyons, saddles, or on steep slopes during a fire is crucial primarily because they can behave unpredictably with fire movement. These geographical features often concentrate heat and wind, which can result in erratic fire behavior. For example, in a chimney or box canyon, the topography can create a funnel effect, intensifying the fire and causing it to accelerate rapidly as it moves upward or through the confined space. This unpredictability increases the risk to both the structures and the firefighters, making it essential to keep a close watch in these areas to anticipate and respond to sudden changes. Understanding how fire interacts with these specific terrain features allows firefighters to better protect lives and property while developing effective strategies for suppression efforts.