Fire and Ice
Fissure is a noun
A fissure is a long, narrow split in the ground resulting from the cracking or parting of the material.
The force of the spaceship smashing into the ground caused a fissure to tear across the face of the earth.
Avalanche is a noun
An avalanche is a large mass of snow or rock falling quickly down the side of a mountain.
An avalanche tumbled down the mountain after Austin's horrid yodeling shook the snow loose from a cliff.
Mt. Saint Helens erupted because an earthquake caused the entire north side to slide down the side of it, releasing the pressure that had been building up inside. Trees were snapped in half by the wind created by the explosion, and ash flew 80,000 feet in the air. The blast killed 57 people in the nearby towns, and the entire forest around the mountain and its animals were annihilated as well. Also, the landslide from Mt. Saint Helens completely clogged the Toutle River.
The ''Big One'' earthquake would be the most devastating to Western Washington. In large cities like Seattle and Tacoma, many people are living there and a lot of buildings are close together. If an huge earthquake hit, the buildings would most likely collapse, crushing all the citizens, and in turn knocking over even more buildings, which would kill even more people. Also, the roads and freeways would be ravaged, leaving survivors stranded where they were. Water pipes could burst, causing flooding. Altogether, entire cities could be flattened, except for perhaps extremely earthquake-resistant buildings such as the Space Needle.