Another very important climatic condition affecting shipping in particular, is ice. Certain ports freeze for varying periods of time during winter and it is important to be aware  of where  ice  conditions  are  found  and  the  time  of  year  the  condition  is prevalent.

In general terms, apart from Arctic/Antarctic regions, the main areas where ice affects shipping are:

A- The Baltic Sea between 1st November and 31st March, e.g.: St Petersburg, Helsinki, Luleå, and Stockholm.

B- The St. Lawrence River between 31st December and 31st March e.g. Montreal, Baie Comeau, Port Cartier.

C- The St. Lawrence Seaway between 15th December and 1st April (the usual opening and closing dates for vessels transiting the Seaway, which may vary from year to year depending upon the severity of the winter). The St. Lawrence Seaway Authority, in order to avoid vessels being trapped in the Great Lakes, publishes the proposed closing date of the Seaway well in advance. Whilst they may still allow vessels to pass through the Seaway after the official closing date, subject to weather conditions, a heavy fine for each day the vessel delays may also imposed on an escalating basis.

FOW – First Open Water – means the first date at which vessels can enter an area of ice in relative safety although additional insurance premiums would still have to be paid over and above normal rates.

Additional to these main areas, ice conditions are prevalent in Albany, situated on the Hudson River and Churchill also has its peculiarity, being situated in remote Hudson Bay and open only for navigation between end July and October. Ice conditions also affect the west coast of British Columbia, the east coast of Russia, Northern China and North Korea, between October to May, and the Black Sea ports of Russia and Romania.

Obviously, advancement in ship design has brought forth the ‘ice breaker’ whose job is to endeavor to keep ice restricted ports open throughout the winter, especially in the Baltic and the Gulf of St. Lawrence. However, in most years, the severity of the winter conditions usually stop even those specialist vessels operating totally successfully.

Finland and Russia lead in development of icebreakers, including the use of nuclear power. Reports and forecasts about ice conditions in the Northern Hemisphere are made readily available every winter. BIMCO (Baltic International Maritime Council) publish these for North West Europe and Scandinavia and the Canadian Government do the same for ice in their waters.

Merchants whose usual ports and routes are closed by ice must resign themselves to trading only during the open season or using alternative means of transport, such as rail, to or from ports not affected by ice, such as Narvik or the Atlantic Seaboard ports of Canada.

It must be remembered that severe weather conditions do not merely interfere with safe navigation. Cargo handling operations in ports and interior transport routes may also face difficulties. In severe cold, for example, steel becomes more brittle and machinery can fail as a result. Diesel oil becomes waxy or freezes, and of course human beings cannot function properly for long in extremes of temperature. Monsoon rain is bound to disrupt cargo handling and may well cause delays to inland transport. Tropical storms can similarly wreak havoc with damage to port installations, warehouses, road and rail transport as well as ships in port.