Believe09,
IMHO...just a local perspective
Regarding the current in the local waterways. The river (at the base and running through Chattanooga) definitely has the strength, speed and depth to conceal and/or carry a vehicle. Large vessels and barges use this area on a regular basis.
The river here is not "flooded" and nothing is impeding local recreation or commerce in the vacinity.
The smaller creeks on the mountain and around the base have been higher than normal after the rains, but water levels seem to be going down quite a bit. A couple of spots I have been watching have gone down too low to conceal a Jeep. Also, most of the creeks around are very curvy and rocky with boulders jutting out...most likely a vehicle would just get jammed-in stuck if it were to enter.
Also, here on the mountain most of these could be easily walked/searched. If the locals here could take a little time and visually check their property these areas could be expediantly cleared. Please keep in mind that although a lot of creeks show up on the map it is not as ominous as it looks. For example, one of those adjoins my property and is at an 3 year record high of about 9" (inches) deep and 2 1/2' (feet) at it's widest. During heavy rains it does swell to about 4' (feet) deep and get up to 80' (feet) wide. Subsides back to normal about an hour after the rain stops.
I guess that what I am trying to share with those who can't actually experience it here locally, is that although there may be a few spots in the immediate vacinity which could be concealing a Jeep, unless it is in the river itself, I am more inclined to think it would be in the woods, down a gully. Is common knowledge here that there a several out of the way ledges and caves for an individual to camp if they were inclined to do so or if they were injured (God forbid), and could not walk to safety.
Forgive me please as I add one more thing regarding cell phones and then I promise to give all of you a reprieve. The locals here will understand and may not give it much thought...one of the things that you just learn to live with on the mountain is very sporadic and sometimes sporadic cell and car satellite signals. Coming up and down the mountain it is not uncommon to disconnect and reconnect two or three times with either.
Again, thank you for letting me try to help by shedding some local light on the geography. Just trying to help bring Gail home!