Where glaciers meet the sea

Here in Glacier Bay National Park in the US state of Alaska, vast ice rivers carve the landscape and occasionally calve icebergs into the sea. Glaciers begin life high in the mountains, where vast amounts of snow pile up in depressions, compacted by the weight of more snow falling on top. Gradually the snow turns to ice and eventually begins to slide downhill – once it’s moving, it’s a glacier.
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