A chilling wind whips through the hollow. Winter's bite grips your spine. The very air you breath stings. Snow swirls all around you, yet, the trees... the trees are motionless in the gale, unaffected by the cold, biting winds.
Magic should have side effects, both expected and unexpected - fortuitous and deplorable. Expected side effects add anticipation, while unexpected ones increase the drama of the scene. The result can be comedic or dire, it dpends on which circumstances work best for your game.