Question

which statement best describes the effect of the eruption of mount saint helens?
ash clouds blocked out the sunlight, and the ash covered everything on the ground.
the eruption disrupted prevailing wind patterns.
buildings, bridges, and roads collapsed due to major widespread flooding and mudflows.
the eruption caused the erosion of rocks into tiny fragments.

Explanation:

When Mount Saint Helens erupted, one of the significant effects was the generation of major widespread flooding and mudflows. These mudflows and floods had enough force to cause buildings, bridges, and roads to collapse. Ash clouds blocking sunlight and covering the ground is more characteristic of some other volcanic eruptions (like Krakatoa in terms of sunlight blocking). Volcanic eruptions don't typically disrupt prevailing wind patterns in a major long - term way. And while there is some rock fragmentation during an eruption, the most impactful and well - known effect related to infrastructure destruction from Mount Saint Helens was due to flooding and mudflows.

Answer:

Buildings, bridges, and roads collapsed due to major widespread flooding and mudflows.