My sources here at Goddard say that they're never going to land at White Sands again if they can help it. The one time they did, the damage to the tiles from the blowing sands was considerable.

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Everything I need to know I learned through Googling.

Out of curiosity. How much time would they have to bail out? A five minute window? Ten?
I’m assuming there is a preset range of altitudes and speed that would allow this.

Orbiter would be put on autopilot at about 25,000 ft. NASA estimates crew of eight could bail out within 90 sec (about 12 sec per crewmember), which should be completed before reaching 10,000 ft.

From that point the vehicle would take approx 90 more sec. to descend to 2,000 ft (180 sec. total from beginning sequence). So there should be additional time in case someone was slow.

http://spaceflight.nasa.gov/shuttle/.../inflight.html

Despite the limitations it's vastly better than before Challenger when the only option was an ocean ditching, considered non-survivable for structural reasons.