Good question!

We have monitored the ice thickness on our main reference lake (Lake 239) since 1969.

The maximum ice thickness we have found on this lake was 82 cm, found in March 15th, 1999 (we can easily check our PostgreSQL master database). Lake 239, like many boreal lakes is fairly small (approx. 50 hectares).

From 2016 to 2019 we also undertook a study in collaboration with Natural Resources Canada that used Ground Penetrating Radar to examine how lake ice thickness was influenced by lake size. In general, our results indicated that as lake size increases, so does the maximum thickness of the ice. The difference from the smallest lake (4 hectares) to the largest lake (2400 hectares) in our study was approximately 40 cm. The apparent cause of the difference was the amount of snow cover. Larger lakes have less accumulation of snow on them due to the higher windspeeds that pushed the snow to the lake edges. The lack of snow meant these lakes were less insulated from the cold air temperatures... and more ice developed.