Upon casting wintry glide, you can travel via ice or snow without crossing the intervening space. If you are adjacent to a mass of ice or snow, you can enter it by expending 5 feet of movement. By expending another 5 feet of movement, you can immediately exit from that mass at any point—within 500 feet—that’s part of the contiguous mass of ice or snow. When you enter the ice or snow, you instantly know the extent of the material within 500 feet.
You must have at least 10 feet of movement available when you cast the spell, or it fails. If the mass of ice or snow is destroyed while you are transiting it, you must make a successful Constitution saving throw against your spell save DC to avoid taking 4d6 bludgeoning damage and falling prone at the midpoint of a line between your entrance point and your intended exit point.