Circular halos on snow surface are common sights, but on ice surface halos are seen much less often. When ice surface halos do show up, they are made by oriented crystals and can be rather bright. Such was the case this morning in Oulu, Finland, where subparhelia was photographed by Karin Parker on lake Pyykösjärvi ( 1 ).
Once in similar situation also sub-120° parhelion and subanthelion was seen ( 2 ). If ice is thick enough, it is good take a little walk and and look around for these less conspicuous halos as well.