alarming
appalling
astounding
atrocious
awe-inspiring
awesome
awful
baneful
beastly
dire
direful
dread
dreaded
dreadful
fearful
fell
formidable
frightful
ghastly
ghoulish
grim
grisly
gruesome
hideous
horrible
horrid
horrific
horrifying
macabre
morbid
redoubtable
rotten
schrecklich
shocking
terrible
terrific
tragic
tremendous
unspeakable
horrify
horror
bone-jarring
cataclysmic
catastrophic
devastate
ear-splitting
fearsome
hellish
madden
sicken
terrify
thunderous
unbearable
unbelievable
unforeseen
unimaginable
stupendous