The code describes the ice conditions in port areas, fairways, coastal sections, and marked sea lanes. It is intended, together with the ice charts and the textual ice reports, to inform the ship’s command of the ice and navigation conditions to be encountered. The various sea and fairway districts of each country are designated by letters: AA, BB, CC, and so on. Each district is divided into sections, which have identification numbers from 1 to a maximum of 9.

Key for reporting ice and shipping conditions Baltic Sea Ice Code of 1980 (A_B S_B T_B K_B)

• First number: A_B Quantity and arrangement of sea ice
• Second number: S_B State of development of the ice
• Third number: T_B Topography or shape of the ice
• Fourth number: K_B Navigation conditions in the ice

First number: A_B Quantity and arrangement of sea ice

0	Ice free
1	Open water Coverage less than 1/10
2	Very loose ice Coverage 1/10 to 3/10
3	Loose ice Coverage 4/10 to 6/10
4	Dense ice Coverage 7/10 to 8/10
5	Very dense ice Coverage 9/10 to 9+/10
6	Ice pushed together or coherent ice Coverage 10/10
7	Ice outside the edge of the fast ice
8	Solid ice
9	Gully in very dense or collapsed ice or along the edge of the fast ice
/	Unable to report

Second number: S_B State of development of the ice

0	New ice or dark nilas less than 5 cm thick
1	Heller Nilas oder Eishaut 5 bis 10 cm dick
2	Gray ice 10-15 cm thick
3	Grey white ice 15 to 30 cm thick
4	White ice, 1st stage 30 to 50 cm thick
5	White ice, 2nd stage 50 to 70 cm thick
6	Medium thick first year ice 70 to 120 cm thick
7	Ice predominantly thinner than 15 cm with slightly thicker ice
8	Ice predominantly 15 to 30 cm thick with slightly thicker ice
9	Ice predominantly thicker than 30 cm, with slightly thinner ice
/	Unable to report

Third number: T_B Topography or shape of the ice

0	Ice predominantly thicker than 30 cm, with slightly thinner ice
1	Small ice floes – 20 – 100 m across
2	Medium ice floes – 100 – 500 m across
3	Big ice floes – 500 – 2000 m across
4	Vast or giant ice floes or level ice – more than 2000 m across
5	Rafted ice
6	Compacted slush or shuga, or compacted brash ice
7	Hummocked or ridged ice
8	Thaw holes or many puddles on the ice
9	Rotten ice
/	Unable to report

Fourth number: K_B Navigation conditions in the ice

0	Navigation unobstructed
1	Navigation difficult or dangerous for wooden vessels without ice sheathing
2	avigation difficult for unstrengthened or low-powered vessels built on iron or steel. Navigation for wooden vessels even with ice sheathing not advisable
3	Navigation without icebreaker assistance possible only for high-powered vessels of strong construction and suitable for navigation in ice
4	Navigation proceeds in lead or broken ice-channel without the assistance of an icebreaker
5	Icebreaker assistance can only be given to vessels suitable for navigation in ice and of special size
6	Icebreaker assistance can only be given to vessels of special ice class and of special size
7	Icebreaker assistance can only be given to vessels after special permission
8	Navigation temporarily closed
9	Navigation has ceased
/	Unknown