If you do break through the ice:
Don't remove winter clothing. Heavy clothes won't drag you down, but instead provide warmth.
Turn in the water toward the direction you came from, this is most likely the strongest ice.
If you have ice picks, dig the points of the picks into the ice while vigorously kicking your feet to pull yourself onto the surface by sliding forward on the ice.
Roll away from the area of weak ice. Rolling on the ice will distribute your weight to help avoid breaking through again.
Get to shelter and remove your wet clothing, redressing in warm, dry clothing and consume warm, non-alcoholic, non-caffeinated beverages as soon as you can.
Call 911 and seek medical attention if you feel disoriented, have uncontrollable shivering or have any other ill effects that may be symptoms of hypothermia, which is a life-threatening condition.