catastrophe
Forecasts predicted heavy rain and catastrophic flooding.
The world is vulnerable to a catastrophic disruption of its energy supply by terrorists.
The movie shows heroes risking their lives to save Earth from a catastrophic collision with a comet.
If the cells are from a donor, can they be kept from causing a catastrophic immune reaction?
The manager picks the wrong team, with catastrophic results.

SMART Vocabulary: related words and phrases

Accidents and disasters
accident
accidental
accidentally
accidentally on purposeidiom
an accident waiting to happenidiom
calamity
cataclysm
cataclysmic
cataclysmically
catastrophe
disastrous
disastrously
doomsday scenario
dumpster fire
emergency
non-emergency
perfect storm
post-accident
snafu
tragedy

You can also find related words, phrases, and synonyms in the topics:

Dangerous and harmful
Not of good quality
Serious and severe