There are not a lot of options out of DCA, BWI or IAD to Miami or Fort Lauderdale on any airline, much less United, tomorrow morning according to seatcounter.com. UA offers non-stops to Miami out of Dulles, however the 12:15 pm departure is sold out. The only other departure is 5:05pm which won't work. A lot of the trains to DC from Newark or Penn Station are sold out this afternoon as a result of the weather and cancellations. So make sure they have a reservation before sending them to the train station.

Their only option may be to get a ticket on Southworst from BWI to FLL this evening at 8:35pm. They can take the train directly to the BWI Station or rent a car and drive to BWI.

Hope this helps. Good luck. Let us know what happens.

RIP...