History
By the end of the 19th century, the national ice services of several countries bordering the North and Baltic Seas had introduced routine ice observing and reporting systems.
The search for a suitable ice reporting code began very early because a quick and convenient way of transmitting the ice observations to a central body and making them available to users was urgently needed. Shipping traditionally has a large variety of terms designating the different ice phenomena, taking into account regional differences that are attributable to different natural environments. Although today an essential criterion in the assessment of ice conditions still is the extent to which they hinder navigation, additional features describing the ice extent had to be introduced within the framework of the international exchange of ice information required in the wake of World War I.
Requests for more and better ice information on the part of industry and shipping, efforts within the World Meteorological Organization to develop a uniform terminology, the transition to a prolonged shipping season lasting throughout winter in the Gulfs of Bothnia and Finland as well as increasing activities in the coastal areas forced the ice services to continually improve the technology and contents of their information exchange.