From the article:

The port is iced in for much of the year and is accessible only between late July and early November. For example, in 2010 the shipping season was July 28 to Nov. 2. Shallow waters also restrict its development as an ocean port. Despite these restrictions the port remains useful for shipping grain and other bulk cargos because shipping by rail costs several times as much, per ton, as shipping by sea.

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The port is almost entirely reliant on grain from the Canadian Wheat Board (CWB) for its viability. Wheat accounts for 90 per cent of all traffic through the port. According to a November 6, 2008 press release, the CWB shipped 424,000 tons of western Canadian wheat through the port of Churchill during the 2008 shipping season. The first wheat left port on August 8, and the last of 15 freighters left on October 20.

Churchill is the "Polar Bear Capital of the World":

Starting in the 1980s, the town developed a sizable tourism industry focused on the migration habits of the polar bear.

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Many locals even leave their cars unlocked in case someone needs to make a quick escape from the polar bears in the area. Local authorities maintain a so-called "polar bear jail" where bears (mostly adolescents) who persistently loiter in or close to town, are held after being tranquilised, pending release back into the wild when the bay freezes over. It is the subject of a poem, Churchill Bear Jail, by Salish Chief Victor A. Charlo. Polar bears were once thought to be solitary animals that would avoid contact with other bears except for mating. In the Churchill region, however, many alliances between bears are made in the fall. These friendships last only until the ice forms, then it is every bear for himself to hunt ringed seals.