sentences:  In order for needle ice to form there needs to be a process of ice segregation, which only occurs in a porous medium when supercooled water freezes into existing ice, growing away from the ice/water interface.As water permeates the ice, it becomes segregated into separate pieces of ice in the form of lenses, ribbons, needles, layers or strands of ice.Needle ice is commonly found along stream banks or soil terraces.