November 24 ice update

While there has been ice growth in the last six days since we left Churchill, it’s still way behind not only the modern average (1991-2020) for the time of year but especially behind the historical average (1971-1991).

The chart below shows this starkly. The latest ice data analysis is for November 19, five days ago. There was an estimated 6% of Hudson Bay covered in ice. The normal value is 18% and in the 1970s and 80s, the average was 39%. The chart below shows the amount of ice (% of Hudson Bay covered) each year back to 1971. Remember 30% is considered the amount necessary for a majority of polar bears to be out on ice hunting seals. Only THREE other years of the last 52 years have had less ice at this point.

Here’s another good visualization: this analysis is for yesterday, November 23rd. Everything in red is where there should be ice at this time of year (based on the 1991-2020 average) but is not covered. We’re seeing roughly one third of the ice cover we should at this point.

There have been lots of cloudy days lately but Thanksgiving was 'clear enough' to get some good shots from space of what ice there is so far:

Temperatures are running about 5 degrees (F) above normal for the month of November so far. While there have been some bouts of cold,  warm spells have undone much of that. The data below are highs (red bars) & lows (blue) for Churchill, the normal high/low are the dashed black lines:

Hudson Bay wide is pretty similar. The warmest temperatures relative to normal are in the north and west parts of the bay which is also where the ice typically develops first.

The weekly ice graph shows the same thing in a different way. Ice this season is behind and bears are still on shore waiting.

There is some good cold, ice-making weather ahead with single digit high temperatures and overnights subzero. Based on the statistical models I showed in our lectures, the next 7 days should cover about 25% of Hudson Bay with ice, getting it near the 30% for a majority of bears to move out. Many adult, male bears will be making their way out over the coming several days however as the ice develops.