Transmutation [Cold]
Level: Cleric 3, Druid 3, Paladin 3, Ranger 3
Components: V, S, DF, Frostfell
Casting Time: 1 standard action
Range: Medium (100 ft. + 10 ft./level)
Area: One 10-ft. square/level
Saving Throw: Reflex negates
Spell Resistance: Yes
This spell must be cast on a snow field. That snow field instantly freezes, impeding movement through the area. A creature caught within the area can move only at half its normal speed. By making a DC 20 Strength check or a DC 25 Escape Artist check, the creature can move at its normal speed for that round. A creature that succeeds on a Reflex save is not impeded.
Source: Frostburn, page 89.