DewPoint52: It's gone. This area floods frequently. Though the cache was not on the ground, it was low. It had survived earlier floods, but I guess TS Hanna got it.
I decided not to replace it since every heavy rain would put it at risk again. If someone else wants to place one in the area, feel free. (I recommend placing it at least a few feet above ground level.) If no one's put one out by the next time I'm in the area, I might put out another one in a spot that should be safe from flooding.