This quick post follows Ars Magica spells for the creation of The Wall from Game of Thrones, a series based on Frozen (posts 2, 3, 4), and a few spells for cold climates. These spells are more like the tools a wizard could have, rather than theatrical effects based upon TV and film.
Vacillate Between Earth and Ice
Muto Terram / Aquam 25, R: Voice, D: Diameter, T: Part
The Terram based material affected is briefly transformed into ice. The maximum target size is determined by material type, from ten cubic paces for earth, a cubic pace for stone, and a cubic foot for metals. If the selected material is larger than these limits, then only the smaller area is transformed.
(Base 3 to change earth to ice, +2 to effect metal, +2 Voice, +1 Diameter, +1 Part)
Transmute into Ice
Muto Terram / Aquam 15, R: Touch, D: Sun, T: Individual
The targeted object is transformed into ice, affecting up to a cubic foot of material. Requisites are required when cast for any non-terram components.
(Base 3, +1 for general approach, +1 Touch, +2 Sun)
Subsume the Frigid Beast
Rego Aquam 25, R: Sight, D: Concentration, T: Part
This spell alters the ice within the target area so that it is transformed into steam. Anything within the target area will fall as they lack support, and items resting upon these surfaces will be quickly encased when the spell is ended.
If the spell is targeted beneath a specific spot, such as beneath a particular creature a targeting roll is required. The effect is designed to affect a bowl shaped area, with a volume up to 5600 cubic feet, although the maximum volume is not required.
(Base 3, +3 Sight, +1 Conc, +1 Part, +1 size)
Object of Unbreakable Ice
Muto Aquam / Terram 15, R: Touch, D: Sun, T: Individual
The ice object touched is made very strong and non-brittle, gaining resistance to shattering and the resilience of stone. The object may be as large as a small pond.
(Base 4 for highly unnatural substance,+1 touch, +2 sun)
This might have been even lower level except using Concentration allows for the ice material to be moved as steam or have the spell end after only a moment and the ice returns.
Many hundred more new spells for Ars Magica are in the Grimoire.