Tephra is a type of volcanic ash. It's made when the ash and gas from a volcano escape into the air.
To billow is to move or to swell up like a wave. When the wind billows the sail on the boat, the sail is moving in the wind.
Pyroclastic is a type of rock that is formed when hot rocks and ash are thrown up into the air. The hot rocks and ash are mixed together and sometimes explode.
To engulf something is to completely surround and control it. When the waves engulf the shore, they are very high and powerful.
Sulfurous means full of sulfur. Sulfurous soils are poisonous, and they often contain a lot of sulfur.
Flickers are brief flashes of light. They can be seen when you look at a light from a certain angle, or when you move your eyes quickly around.
To sheer something is to cut it very thin. Sheers are often used to make curtains or other cloths very thin and delicate.
The townspeople are the people who live in a town or city. They are usually the people who are most affected by the actions of the mayor or other leaders.
When something is rediscovered, it is found again after being lost or forgotten. This might happen when someone finds a lost object, or when a new discovery is made about a previously unknown topic.