Rivers of ice spill down from the icecap as great glaciers and creep slowly towards the edge of the continent and the sea.

When you get beneath the snout of one of these huge glaciers, you begin to appreciate the immense power and size of the Antarctic ice sheet. The ice here towers 100 feet above me, and the whole front of the glacier is about 2 miles across. But this is a small glacier, the largest glacier in Antarctic and in the world is the Lambert Glacier, and that's 25 miles across. But this is not a place where you want to linger. The glacier moves forward at a rate of about 2/3 of a mile a year and the front-end is continually breaking away to form icebergs. And if one came down now, well, the surge could easily overturn a small boat.

These icefalls disintegrate into brash ice. But when a large chunk of a glacier or an ice sheet breaks away, it floats off as an iceberg. At first these bergs are slab-like. But winds and waves above water and currents below slowly carve them into the loveliest of the shapes. A large berg can survive for up to ten years before it ultimately breaks up and melts. Only 1/5 of an iceberg is above the surface, the rest is hidden beneath the water. Streams of minute air bubbles released from the melting berg carve grooves in its submerged flanks.

words and expressions

spill :溢出, 涌流

disintegrate:分裂成小块；使瓦解

brash:碎片

chunk:大块

flank:侧面