The article you linked says they have the NPS from Great Smokey NP helping:
Quote:
Over 50 members from several agencies have been searching since 1 a.m. Sunday. Authorities are getting assistance from rangers with the Great Smoky Mountains National Park, whom they say have more experience with a large-scale search like this one.

This is good, since when searches get this big they can very quickly turn into a total clusterflock if not properly managed. The NPS along with NASAR has been in the forefront of developing methods for conducting and managing large ground searches.

Best hopes for a successful and happy ending to this search!
_________________________
"Toto, I've a feeling we're not in Kansas any more."
-Dorothy, in The Wizard of Oz