How many times, say during Katrina did this occour

uh, if you are deserted on an island with a few buckets of electronics junk,
your best bet is CW.

if you a prisoner of war, CW could be invaluable in getting a message out.
there are many other cases where CW can be used in channels that don't
support audio.

i am a superior creature because i know CW! ;-)

Gravity