calamitous (
http://definr.com/calamitous)
adj : (of events) having extremely unfortunate or dire
consequences; bringing ruin; "the stock market crashed
on Black Friday"; "a calamitous defeat"; "the battle
was a disastrous end to a disastrous campaign"; "such
doctrines, if true, would be absolutely fatal to my
theory"- Charles Darwin; "it is fatal to enter any war
without the will to win it"- Douglas MacArthur; "a
fateful error" [syn:
black,
disastrous,
fatal,
fateful]