>> reporter: frustrated words from pia scott. tonight she has two choices. >> this is horrible. >> reporter: sleep at a hotel or here at dulles airport. her flight to new york is canceled because of freezing rain. >> the other option is to take amtrak train. >> reporter: take a look at the departure board. canceled, canceled, canceled. >> it's very annoying. >> reporter: the rain and a dip in temperature could cause icy commutes tomorrow morning, and there is a higher chance of ice in the northwest suburbs of d.c. >> it does get pretty bad. every now and then they'll do a good job of cleaning the roads up. >> reporter: inside the salt dome, it holds 2500 tons of salt when it's full. crews will be coming in here with their trucks, removing 400 to 600 tons throughout the night. they're going to take this salt right here and mix it with something called the b mix. >> b mix is basically salt and sand mixture. >> reporter: 1500 v-dot trucks