How do ice berg form

Icebergs form when chunks of ice calve, or break off, from glaciers, ice shelves, or a larger iceberg ... On the iceberg surface, warm air melts snow and ice into pools called melt ponds that can trickle through the iceberg and widen cracks.

Iceberg forms when a glacier

reaches the sea coast and when large chunks of ice calve (break off) and float away.