"Disaster" is probably the closest synonym, but "distress" rather close.
A synonym starting with d of the word calamity is 'disaster'
disaster
Disaster
One option is the word disaster.
That word would be disaster.
A synonym for the word "calamity" that starts with the letter "d" is "disaster." Both terms refer to significant and often sudden events that cause great damage, distress, or loss.
A disaster, like a calamity is a hugely problematic turn of events.
Dazzling is a synonym for beautiful. Delightful is another word for beautiful.
Deluge
dire
Disaster?
(D) Unknow