unexpected
abrupt
electrifying
extraordinary
hasty
headlong
impetuous
improbable
impulsive
more than expected
nerve-shattering
out-of-the-way
past expectation
precipitant
precipitate
precipitous
quick
shocking
speedy
startling
sudden
surprising
swift
unannounced
undivined
unforeseeable
unforeseen
unguessed
unheralded
unhoped for
unlooked-for
unpredictable
unpredicted
unprepared for
without warning
adverse
avoidable
calamitous
catastrophic
disastrous
double-digit
fortuitous
logistical
unacceptable
unavoidable
uncalled
uncalled-for
unconvinced
unexplained
unintended
unplanned
unprecedented
unrealized
unsolicited
unthinkable
untoward
unwarranted
anticipated
dissipated
participated