Polar Bears of Churchill – Waiting for the Ice
By mid-October, cooler temperatures bring a change in the bears. Restless, sensing a change in the season, many return to Churchill and gather along the coast in eager anticipation of the coming ice. Once here, some pace along the coast, roll around the willows, graze on some kelp or spar with a friend.
Most, however, pass the time in a ‘day bed’. A ‘day bed’ is simply a good resting spot, comfortable and sheltered. Preferred locations include willow thickets along the shallow tundra ponds and the deep kelp beds on the coast. There are certain ‘day beds’ along Cape Churchill that are used day after day, often year after year.
Resting is not without its complications. Larger, or simply more aggressive bears, often approach and displace sleeping bears. Once ‘victorious’, however, they may occupy the bed for only a short time.
Many times, the displaced bear will return, after walking a large, cautionary circle back to its original resting area. Once here, it is again, time to rest and wait.
Waiting pays off. With each succeeding tide, a little more ice clings to the shore. Each day, the ice reaches out a little further into the bay. And each day, the bears test the ice more and more.
Though considered a marine mammal, bears still prefer not to get wet in cold temperatures. Walking on newly formed ice, polar bears often spread all four legs further and further apart until their belly almost touches the ice. Their large paws distribute their weight very effectively, allowing them to walk on ice that would
not support the weight of a person…and especially not the weight of a tundra vehicle.
Alternately, they may test the strength of the new ice as they progress, giving a little pump with their front paws. As the shore ice builds so does the bears’ anticipation. By season’s end, many bears will be seen wandering along the ice’s edge, far out onto the bay.
Polar Bears of Churchill – How the Ice Forms
Salt water becomes heavier as it freezes. This leaves a greasy soup of ice washing in and out with the tide, each wave leaving just a little more ice clinging to the shore. In Churchill, high tide returns every 12.5 hours and it does not take long for the shore ice to extend well out into the tidal zone.
As well, Hudson Bay’s watershed extends west to the Canadian Rockies and south to Minnesota. This means that a tremendous amount of fresh water pours into the bay from several northern rivers. This inflow results in brackish water (a mix of salt and
fresh water) along the coast and surface of Hudson Bay. Since freshwater begins to freeze at a higher temperature than salt water, this further contributes to the speed of freeze up.
All the while, the ice builds along the northwestern coast of Hudson Bay. Soon, the ‘grease ice’ forms into little ice floes called pancake ice. A strong north wind and consistently cold temperatures of -20C (-4F) or lower will push this ice together and
pack it onto the coast of Cape Churchill.
Once these sheets have frozen together, it signals the bears’ departure. They will venture out to hunt seals even with only a few kilometres of ice. As winter progresses, the ice continues to encroach eastward until the bay is completely frozen, usually occurring in early December.
Almost every year, initial freeze up occurs around mid-November. However, in both 1991 and 2002, conditions prevailed for an early freeze. The freeze up was so sudden in 1991 that the bears departed near Halloween night. In other years, winter takes its time – 1999 and 2003 saw the bears remain ashore well into December. While a late freezeup is not as critical to the bears’ health as an early breakup, it does result in an extreme increase in polar bear occurrences within the community of Churchill.