Polar Screen (4e Power)

Polar Screen	Wizard 4e Power Type::Attack 9
You create a misty, bluish-white screen of energy. Those that pass through it are coated with ice crystals that painfully chill until they thaw.
4e Power Usage::Daily  Arcane, Conjuration, Cold, Implement
4e Power Action Type::Standard Action	Area wall 8 within 10 squares
Effect: You create a wall that consists of contiguous squares filled with freezing blizzard. It can be up to 8 squares long and up to 4 squares high. The wall lasts until the end of your next turn. Any creature that starts its turn adjacent to the wall takes 3 + Intelligence modifier cold damage. If a creature moves into the wall's space or starts its turn there, the creature takes ongoing 5 cold damage (save ends). The squares occupied by the wall provide concealment and are difficult terrain.
Sustain 4e Sustain Action Type::Minor: The wall persists.