Ash is another volcanic danger.
Unlike the soft, fluffy bits of charred wood left after a campfire, volcanic
ash is made of sharp fragments of rocks and volcanic glass each less than two millimeters across. The
ash forms as the gasses within rising magma expand, shattering the cooling rocks as they burst from the
volcano's mouth. It's not only dangerous to inhale, it's heavy and builds up quickly. Volcanic ash can
collapse weak structures, cause power outages, and is a challenge to shovel away post-eruption.
Can we predict volcanic eruptions?
Volcanoes give some warning of pending eruption, making it vital for scientists to closely monitor any
volcanoes near large population centers. Warning signs include small earthquakes, swelling or bulging of
the volcano's sides, and increased emission of gasses from its vents. None of those signs necessarily
mean an eruption is imminent, but they can help scientists evaluate the state of the volcano when
magma is building.
However, it's impossible to say exactly when, or even if, any given volcano will erupt. Volcanoes don't
run on a timetable like a train. This means it's impossible for one to be “overdue” for eruption—no
matter what news headlines say.