Icebergs in the Antarctic sometimes have stripes, formed by layers of snow that react to different conditions:

• Blue stripes are often created when a crevice in the ice sheet fills up with meltwater and freezes so quickly that no bubbles form.
   
• When an iceberg falls into the sea, a layer of salty seawater can freeze to the underside.  If this is rich in algae, it can form a green stripe.
    
• Brown, black and yellow lines are caused by sediment, picked up when the ice sheet grinds downhill towards the sea.

       

Antarctic temperatures can be so blistering cold that water freezes the instant it touches the air.  This wave actually froze in mid-crest: