Volcanic eruptions are among the most terrifying and dramatic forces in nature. Lava flows usually burn or bury everything in their path, and the flows can continue for miles and miles. Suffocating ash flows—a mix of hot gases, pumice, rock fragments, and bits of glass—can also accompany an eruption. Debris flows are especially treacherous. Water from lakes or rivers, heavy rain, or melting snow can cause debris on the flanks of a volcano to form into a fast-moving "mudflow" of rock, ash, and cinders. These flows can occur with little warning, and a wall of mud can cover an entire city, claiming thousands of victims before they can react. How can I write a clincher sentence?