Which topographical feature pushes fire faster during uphill runs?

In the context of wildland fire behavior, a saddle can influence fire spread, particularly during uphill runs, due to its geographical characteristics. Saddles are low points between two higher areas, often found on ridges. When a fire encounters a saddle, it can move more quickly because it is moving towards the higher elevation, utilizing the slope to gain momentum and allow heat and flames to rise more effectively.

As fire travels uphill, it takes advantage of the preheating effect that occurs when flames are directed toward the unburnt fuel above. Therefore, a saddle can act as a channel that funnels fire upwards, contributing to faster spread rates during uphill runs. This feature, along with the heat rising and preheating the surrounding fuels, enhances the fire's intensity and the speed at which it travels uphill.

Other topographical features like flatlands, hollows, and plateaus do not provide the same conducive conditions for rapid fire spread during uphill runs, which is why they are less likely to be correct answers in this scenario. Flatlands do not present an incline for the fire to ascend, while hollows can contain heat and may not facilitate the same upward movement. Plateaus, being flat and elevated, are also not conducive to rapid uphill fire runs