The egg of the new Frost Dragon can be found in Level 10 mountain and you need to send a great dragon or any elemental dragon in order to find the egg of frost dragon. To make the new outpost u must have spectral outpost check this link :
U need to be level 5 and posses the frost dragon egg and capture a level 10 mountain to make the new outpost.
Good luck And happy Hunting. . . .