Two of the three California gray whales trapped for two weeks in the Arctic Ocean ice near Barrow, Alaska, surface in a small breathing hole Thursday. Rescuers decided Thursday to use a helicopter to drop a 41/2-ton concrete slab at daybreak Friday that could punch a trail through the foot-thick ice. Sub-zero temperatures, darkness and mud have frustrated efforts to move an icebreaking barge into the area. Volunteers have been using ice picks, chain saws and de-icers donated by a Minnesota family business to enlarge the two original holes and punch new ones.