School evocation [cold]
Casting Time 30 minutes
Components V, S, M (a piece of quartz or rock crystal)
Effect ice wall whose area is up to [6/8/10/12/14] 10-ft. squares, or hemisphere of ice with radius of [10/12.5/15/17.5/20]-ft.
Saving Throw reflex negates; Spell Resistance yes
This spell creates an plane of ice or a hemisphere of ice (anchored to the ritual node), depending on the version selected. A wall of ice cannot form in an area occupied by physical objects or creatures. Its surface must be smooth and unbroken when created. Fire can melt a wall of ice, and it deals full damage to the wall (instead of the normal half damage taken by objects). Suddenly melting a wall of ice creates a great cloud of steamy fog that lasts for 10 minutes.
Ice Plane: A sheet of strong, hard ice appears. The wall is [6/8/10/12/14] inches thick. It covers up to [6/8/10/12/14] 10-foot-square areas. The plane can be oriented in any fashion as long as it is anchored to the ritual node.
Each 10-foot square of wall has 3 hit points per inch of thickness. Creatures can hit the wall automatically. A section of wall whose hit points drop to 0 is breached. If a creature tries to break through the wall with a single attack, the DC for the Strength check is [22/24/26/28/30].
Even when the ice has been broken through, a sheet of frigid air remains. Any creature stepping through it (including the one who broke through the wall) takes 1d6 points of cold damage + [8/10/12/14/16] (no save).
Hemisphere: The wall takes the form of a hemisphere whose maximum radius is [10/12.5/15/17.5/20] feet. The hemisphere is as hard to break through as the ice plane form.
Once per day, while within 100 feet of the ritual node, you can restructure the wall of ice as a standard action. It is possible to trap mobile opponents within or under a wall of ice, provided the wall is shaped so it can hold the creatures. Creatures can avoid entrapment with successful Reflex saves. If they make their reflex save, the spell fails entirely for the day.