Ice Information: ci Si bi Di zi

ci -- Concentration or arrangement of sea ice

0 -- No ice
1 -- Ship in open lead more than 1 n. mile wide or ship in fast ice with boundary beyond limit of visibility
2 - 5 Ice concentration uniform
2 -- Open water or very open pack ice, < 3/8 concentration
3 -- Open pack ice 3/8 to < 6/8 concentration
4 -- Close pack ice 6/8 to < 7/8 concentration
5 -- Very close pack ice 7/8 to < 8/8 concentration
6 - 9 Sea ice concentration not uniform
6 -- Strips and patches of pack ice with open water between
7 -- Strips and patches of close or very close pack ice with areas of lesser concentration between
8 -- Fast ice with open water, very open or open pack ice to seaward of the ice boundary
9 -- Fast ice with close or very close pack ice to seaward of the ice boundary
/ -- Unable to report, because of darkness, poor visibility or because ship is more than 0.5 n. mile away from ice edge

Si -- Stage of development

0 -- New ice only (frazil ice, grease ice, slush, shuga)
1 -- Nilas or ice rind, < 10 cm thick
2 -- Young ice (grey ice, grey-white ice) 10-30 cm thick
3 -- Predominantly new and/or young ice with some first-year ice
4 -- Predominantly thin first-year ice with some new and/or young ice
5 -- All thin first-year ice (30-70 cm thick)
6 -- Predominantly medium first-year ice (70-120 cm thick) and thick first-year ice (>120 cm thick) and some thinner (younger) first-year ice
7 -- All medium and thick first-year ice
8 -- Predominantly medium and thick first-year ice with some old ice (usually more than 2 meters thick)
9 -- Predominantly old ice
/ -- Unable to report, because of darkness, poor visibility or only ice of land origin visible or because ship is more than 0.5 n. mile away from ice edge

0 -- No ice of land origin
1 -- 1-5 icebergs, no growlers or bergy bits
2 -- 6-10 icebergs, no growlers or bergy bits
3 -- 11-20 icebergs, no growlers or bergy bits
4 -- Up to and including 10 growlers and bergy bits - no icebergs
5 -- More than 10 growlers and bergy bits - no icebergs
6 -- 1-5 icebergs with growlers and bergy bits
7 -- 6-10 icebergs with growlers and bergy bits
8 -- 11-20 icebergs with growlers and bergy bits
9 -- More than 20 icebergs with growlers and bergy bits - a major hazard to navigation
/ -- Unable to report, because of darkness, poor visibility or only sea ice is visible

0 -- Ship in shore or flat lead
1 -- Ice edge towards NE
2 -- Ice edge towards East
3 -- Ice edge towards SE
4 -- Ice edge towards South
5 -- Ice edge towards SW
6 -- Ice edge towards West
7 -- Ice edge towards NW
8 -- Ice edge towards North
9 -- Not determined (ship in ice)
/ -- Unable to report, because of darkness, poor visibility or only ice of land origin is visible

0 -- Ship in open water with floating ice in sight
1 -- Ship in easily penetrable ice; conditions improving
2 -- Ship in easily penetrable ice; conditions not changing
3 -- Ship in easily penetrable ice; conditions worsening
4 -- Ship in ice difficult to penetrate; conditions improving
5 -- Ship in ice difficult to penetrate; conditions not changing
6 - 9 Ice difficult to penetrate; conditions worsening
6 -- Ice forming and freezing together
7 -- Ice under slight pressure
8 -- Ice under moderate or severe pressure
9 -- Ship beset
/ -- Unable to report, because of darkness, poor visibility