Having repaired miniature electronic circuits after a ~ a day in salt water (while energized) I wouldn't hold out much hope for the cards
".... An impact switch, mounted in the aft avionics compartment, controls power to the recorder.
If the impact switch is subjected to a 2.5 G shock, the recorder is electrically disconnected to prevent further recording and erasure. ....."
From Ref. 11 of the Wikipedia link posted by jcjeant.
And maybe to minimise corrosion? Regards,
