...but the largest of them were all sitting in the same area. We learned that this was where the terminal moraine of the Columbia Glacier is located (basically the depth of the water goes from deep water to rather shallow water). The terminal moraine traps the tall icebergs since they are not shallow enough to get over the moraine. The guide told us that usually there is so much ice beyond this point that it is too dangerous to go any further. We lucked out!! The ice beyond the terminal moraine was not bad at all, so we got the chance to proceed to the Columbia Glacier!!