So...
Spell-Like Abilities: 3/day—freezing fog (adult or older), wall of ice (old or older); 2/day—ice shape (as stone shape, but applies to ice instead of stone; juvenile or older); 1/day—searing light (ancient or older).
We still need a great wyrm ability. Maybe something like one of the following?
Blizzard (Frostburn)
Transmutation [Cold]
Level: Drd 5, Winter 5
Components: V, S
Casting Time: 1 round
Range: Long (400 ft. + 40 ft./level)
Area: 100 ft.-radius/level spread
Duration: 1 round/level
Saving Throw: Fortitude partial
Spell Resistance: No
Immediately upon completion of this spell, the temperature drops to below freezing and a powerful blizzard erupts in the area. Visibility is reduced to zero, making Spot, Search, and Listen checks and all ranged attacks impossible. Unprotected flames are automatically extinguished and protected flames have a 75% chance of being doused. Creatures unprotected from the cold must make a Fortitude save or take 1d6 points of nonlethal cold damage.
One foot of new snow falls each round. Movement within the area is impeded, depending on the creature's size and depth of snow (for movement in a snow field, see page 12).
Obedient Avalanche (Spell Compendium)
Conjuration (Creation)[Cold]
Level: Cold 9, Sor/Wiz 9
Components: V, S
Casting Time: 1 standard action
Range: Medium (100 ft. + 10 ft./level)
Effect: 20-ft.-radius avalanche of snow centered on a point in space; see text
Duration: Instantaneous
Saving Throw: Reflex half or Reflex negates; see text
Spell Resistance: No
You summon an avalance of snow out of a rift in midair, burying your foes and sending them to a frosty death.
An obedient avalanche spell affects creatures differently, depending on where they are in relation to the avalanche.
Within 20 Feet of the Center Point: Creatures take 1d8 points of damage per two caster levels (maximum 10d8) and an additional 1d6 points of cold damage per two caster levels. A successful Reflex save halves the damage. Creatures who fail their saves are also buried (DMG 90). All squares within 20 feet of the center point are covered in heavy snow (DMG 94), which persists as long as ordinary snow would. A buried creature can free itself with a DC 20 Strength check as a full-round action, and can be dug free by others (a single creature working alone requires 1 minute to free a trapped creature). A trapped creature is unable to move, and cannot cast spells with somatic components, and any material components must be in hand.
Between 20 feet and 40 feet of the Center Point: Creatures take half as much damage from the impact of the avalanche as the creatures nearer the center point took (Reflex save negates). Creatures who fail their saves must also resist the force of the snow moving past them as if they were being bull rushed. The snow has a +13 attack bonus (+5 for effective Strength of 20 and +8 for effectively being Huge) on the bull rush check, and it pushes characters away from the center point of the spell. All squares in the 20-foot to 40-foot ring are covered in light snow (DMG 94), which persists as long as ordinary snow would.
Terrain and Structures: The avalanche uproots small trees and other vegetation automatically, and it leaves a trail of light rubble (DMG 91) even after the snow melts. Structures struck by an obedient avalanche take 1d6x10 points of damage.
An obedient avalanche extinguishes all flames it touches, whether normal or magical.
Iceberg (Frostburn)
Evocation [Cold]
Level: Sor/Wiz 9
Components: V, S
Casting Time: 1 standard action
Range: Long (400 ft. + 40 ft./level)
Area: 60-foot radius
Duration: Instantaneous
Saving Throw: None or Reflex half; see text
Spell Resistance: Yes
Iceberg is a brutal and direct spell. When cast, the spell creates a single large block of ice that drops from the sky onto a spot you select. The iceberg then shatters if it encounters a solid surface. Elephant-sized blocks of ice scatter in all directions, affecting nearby creatures based on how far they are from the center of the area.
Within 20 Feet of the Center Point: Any creature or object directly beneath the iceberg takes 20d6 points of crushing damage (no save) and is buried in snow (see page 90).
Between 20 Feet and 40 Feet of the Center Point: Creatures and objects in the middle section of the area also take 20d6 points of crushing damage, but are entitled to a Reflex save for half damage. They are buried in snow (see page 90).
Between 40 Feet and 60 Feet of the Center Point: Creatures in the outermost section may be struck by flying debris for 10d6 points of damage. They are entitled to a Reflex save for half damage, and are not buried regardless of whether the saving throw is successful or not.
Ice Claw (Spell Compendium)
Evocation [Cold]
Level: Sor/Wiz 7
Components: V, S, F
Casting Time: 1 standard action
Range: Medium (100 ft. + 10 ft./level)
Effect: 10-ft. ice claw
Duration: 1 round/level (D)
Saving Throw: None
Spell Resistance: Yes
You finish the evocation and a great white claw appears before you, cold air wafting off its crystalline surface.
This spell creates a massive reptilian claw made of ice. The ice claw can make one grapple attack per round. Its attack bonus and grapple modifier are equal to your caster level + your Int modifier or Cha modifier (for wizards and sorcerers, respectively) + 7 for the claw's Strength (24). IN any round when the claw is grappling a target, it deals 1d8 points of cold damage.
The claw can attack on the round it appears. Directing it to change targets is a standard action. It always attacks from your direction and does not get a flanking bonus or help a combatant get one. The claw has as many hit points as you do when undamaged and is AC 20 (+10 natural). It takes damage as a normal creature, but most magical effects that do not deal damage do not affect it. The claw cannot push through a wall of force or enter an antimagic field. It suffers the full effects of a prismatic wall or prismatic sphere. The claw has your saving throw bonuses. Disintegrate or a successful dispel magic destroys it. It has immunity to cold and vulnerability to fire.
Focus: A white leather glove and a piece of clear rock crystal.