Don't get trapped in the Smokies by deep snow. Have a plan, A, B and C that does no include a rescue or a trip to the hospital or worse. This is one Thru-hikers plan. She had a 3 season tent, 20 degree bag and a warm coat and no special snow walking equipment. Bring extra food just in case. Have a cell phone. Don't go alone. Never leave the AT. Tell someone at home when you start and when to expect a call from you again. Take the trouble of calling the ranger station.
Plan A, Get a good weather report while in Fontana Village. If less than 1 foot of snow is reported by the Park Rangers along the trail inside the park and there 4 clear days ahead....hit the trail and re-look at conditions at Newfound gap in 3 or 4 days. If everything is good for 2 or 3 days...keep hiking and finish the park.
Plan B, If the snow is deeper than one foot and the weather looks good for melting in the next day.....take a zero or 2 zeros or 3 zeros.
Plan C, If the snow is deeper than 3 feet or a big snow producing weather system is coming in the next 3 days....get a shuttle to Standing Bear in Davenport gap and hike North to Hot Springs. When weather conditions improve or the deep snow melts get a shuttle back to Fontana and do the park.
Plan D, The weatherman got it wrong, Day 1 at Mollies Ridge or Russel Field or Spence Field and there is 2 feet of snow....head South back to Fontana. If more than 2 feet of snow...stay put and wait however many days it takes. If you are North of Newfound gap this will apply to Crosby Knob and Tri-Corner Shelters.
3 feet of snow will make drifts 5 or 6 feet deep. Only a fool walks blindly into a trap.