Memory Conforms With What We Now Believe.

The lake used to be frozen over by New Year's. Sadly, no longer.

The above is a quote from someone I know on Facebook who is a "worrier" when it comes to global warming.

He was refering to Lake Champlain. I was in Vermont for eight years (1992-2001) and I had vaguely remembered that it froze the first winter I was there and the second but then maybe only once after that, so I was curious if my experience was typical.

The records were easy to find.

The records go back to 1816 and there is no year in which the lake was frozen by New Year's. January is the most common month though. Also, while the lake did freeze more often in the past, 1851-1918 without missing a year, this is long before this guy was alive. In his personal memory, it freezes about half the winters. The trend is slight: 19 times in his first 30 years of life and 15 times since then.

Probably the largest influence, besides confirmation bias, is that the lake has gone 5 years in a row of not freezing. By March, we will know if it has made it 6 years in a row.

Update: It did in fact go 6 years without freezing since it didn't freeze in 2013. It has come back with a fury though: Frovze in mid Feb in 2014 and 2015.