Ice Chart Colour Codes International Ice Chart Working

Ice Chart Colour Codes International Ice Chart Working Group, October 2000 John Falkingham, Canadian Ice Service

WMO Hatching Codes Total Concentration

WMO Hatching Codes Stage of development and thickness

CIS Manice Colour Code Hatching = total concentration Colour = predominant ice type

MANICE Colour Code

Canadian Ice Service Colour Code • Primarily intended for marine navigation use – multi-year ice emphasized – thin ice forms not prominent • Green-yellow-red colouring based on Total Concentration except: – Ice less than 15 cm thick is not considered in Total Concentration

Canadian Ice Service Colour Code Open or Bergy Water Blue = open or bergy water Ice types Thicker than 15 Cm Green = 1 to 3 tenths of ice thicker than 15 cm Yellow = 4 to 6 tenths of ice thicker than 15 cm Orange = 7 to 8 tenths of ice thicker than 15 cm Red = 9 to 10 tenths of ice thicker than 15 cm Old Ice . Purple Dash Lines indicate presence of 1 to 4 tenths old ice Solid Purple indicates presence of more than 4 tenths old ice Thin Ice Blue stars indicate predominance of ice thinner than 10 cm Red stars indicate predominance of ice 10 -15 cm Fast Ice Black regardless of thickness

Canadian Ice Service Colour Code Ice coverage in tenths Ice Thicker Than 15 cm open or bergy water (less than 1/10) 1 to 3/10 4 to 6/10 7 to 8/10 9 to 10/10 fast ice Predominant Ice - 15 cm or less than 10 cm (new ice) 10 to 15 cm (grey ice) Old Ice 1 to 4/10 5 to 10/10

Colour Code Observations • Stars or other symbols scattered across a chart tend to clutter the display - problem for ECDIS • “Green” may not be appropriate for any amount/type of ice – falsely indicates a “go” condition? • One colour code will not suit all users – let users choose their own colour scheme tailored to their needs? – but have “default” international standard • International standard colour code should be very simple and intuitive

Tentative Proposal Open water / Bergy water 1 -3 tenths ice 4 -6 tenths ice 7 -8 tenths ice ignore thin ice (<15 cm) 9 -10 tenths ice Fast Ice any thickness Any concentration of thin ice (<15 cm) National practice to superimpose symbols (e. g. stars, bars) to delineate significant ice features (e. g. multi year ice)