Final answer:
Pyroclastic flows can cross bodies of water due to their density and momentum. They are different from water waves, which only transfer energy. Additionally, the latent heat of fusion can prevent nearby air temperatures from falling significantly below 0°C.
Step-by-step explanation:
Pyroclastic flows can indeed cross bodies of water. These flows are dense, fast-moving and composed of hot gases, ash, and rock. Unlike water waves, which transfer only energy, pyroclastic flows carry their physical material with them. When they reach water, they can maintain their momentum and potentially cross small bodies of water.
The ability of pyroclastic flows to traverse water does not depend on the water absorbing heat quickly, but rather on the high density and velocity of the flow itself. On the other hand, latent heat of fusion of water can influence air temperatures.
As water freezes, it releases heat, which can prevent air temperatures around large bodies of water from falling significantly below 0°C, providing a sort of temperature buffer for the surrounding area.