Ice Walk. The dragon can move across and climb icy surfaces without needing to make an ability check. Additionally, Difficult Terrain composed of ice or snow doesn't cost it extra movement.
Multiattack. The dragon makes three Rend attacks.
Rend. Melee Attack Roll: +7, reach 10 ft. Hit: 9 (2d4 + 4) Slashing damage plus 2 (1d4) Cold damage.
Cold Breath (Recharge 5–6). Constitution Saving Throw: DC 15, each creature in a 30-foot Cone. Failure: 40 (9d8) Cold damage. Success: Half damage.