Ice also closes many ports in the Baltic Sea and other places around that north-west corner of the European continent as well as parts of Alaska; the Hudson Bay is closed for a longer time than it is open. Winter weather generally can be troublesome especially in the North Atlantic where storms can cause severe delay, even structural damage. At the other end of the climatic scale there are a variety of storms in the tropical areas. Monsoon gales and torrential rains around the Indian sub-continent in June, July and August can seriously disrupt cargo working. Even more violent are the cyclonic storms known as hurricanes in the Caribbean area (August/October) and in the South Pacific (December/March). Typhoons in the Far East any time between May and January but more likely July/October. In the southern Indian Ocean such storms are simply called by their meteorological name – cyclones – which are at their worst between November and May and some catastrophic wave formations occasionally result off the coast of Southern Africa where ships have even been known to break in two. Off the west coast of Australia the cyclones (known as Willy-willies when they reach land) are at their most violent between January and March. By the way, cyclones in the northern hemisphere rotate anti-clockwise whilst south of the equator they spin clockwise. Part of the duties of the Operations Department will be to ensure that all hires and freight are collected and that their receipt is timely and correct in accordance with the terms of the Charter party. This is the income derived from a time charterer and it is usually paid every 15 days, in advance. The Charterers may make various deductions from the hire, all of which must be specified in the Charter party. It is customary that with the first hire payment the Charterers add the value of the bunkers remaining on board at the time of delivery of the vessel. From the last hire payment the Charterers deduct the value of the bunkers that will probably remain on board the vessel on redelivery.