The correct answer is option 2: Terrestrial. An avalanche is a type of terrestrial disaster.

Terrestrial refers to anything related to the Earth or the land. In the context of natural disasters, terrestrial disasters are those that occur on land. Examples of terrestrial disasters include earthquakes, landslides, volcanic eruptions, and avalanches.

An avalanche is a sudden and rapid flow of snow, ice, and rock down a mountainside. They are typically triggered by factors such as heavy snowfall, steep slopes, and disturbances in the snowpack, such as the movement of skiers or loud noises. Avalanches can cause significant damage to infrastructure, homes, and vegetation, as well as pose a threat to human life.

It`s important to differentiate terrestrial disasters from other types of disasters. Atmospheric disasters, option 1, refer to weather-related events such as hurricanes, tornadoes, and storms. Aatic, option 3, is not a recognized term in the context of disasters. Biological disasters, option 4, refer to outbreaks of diseases, epidemics, or pandemics.

Therefore, the correct option is option 2: Terrestrial.