Polar Chill

 
Prerequisite(s): Exposure to cone of cold or ice storm spell.
 
Benefit: Once per day, you can make the ground icy in a 20-foot-radius spread around you. Each square in that area becomes covered with ice, so it takes two squares of movement to enter each square, and the DC of Balance and Tumble checks there increases by 5. A DC 10 Balance check is required to run or charge across the ice. The ice remains for 1 minute or until exposed to fire. You can't use this feat if you aren't touching the ground, and it doesn't work if the air temperature is above 1.00 degrees.
 
Source: Unearthed Arcana