calamity
The team suffered a calamitous defeat yesterday.
World oil markets over the years have weathered calamitous events.
She was riding to the hospital on a bicycle and suffered a calamitous accident along the way.
Global warming of five degrees could be calamitous.
The nuclear reactor overheated to potentially calamitous levels.

SMART Vocabulary: related words and phrases

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