What is the smallest amount of volcanic ash on a roof that would commonly cause it to collapse?
A) no amount of ash would cause collapse; it is too light to be a problem
B) more than about 3 cm
C) more than about 20 cm
D) more than 2 meters
E) more than 20 meters

Question

Quizplus · Accepted Answer

Volcanic ash is a very fine-grained material that can accumulate on roofs and other surfaces. When it gets wet, it can become very heavy and can cause roofs to collapse. The amount of ash that is required to cause a collapse depends on the weight of the ash, the size of the roof, and the strength of the roof. In general, more than about 20 cm of ash is enough to cause a roof to collapse.

What Is the Smallest Amount of Volcanic Ash on a Roof