Lake Huron, January 13, 2023
PHOTO COURTESY OF NOAA COASTWATCH GREAT LAKES
Mild temperatures this year have impacted ice coverage and thickness on all the Great Lakes, reports CBC, a trend that is consistent with years over the past decade. According to Jay Austin, who studies Lake Superior at the University of Minnesota Duluth’s Large Lakes Observatory, “If you look at ice coverage prior to 1998, most years we had moderate to heavy ice cover. Then ’98 itself was an El Niño year with very low ice coverage and we’ve had lots of those extremely low coverage years since then,” he told CBC. “It does really appear the atmosphere sort of shifted into a different mode in 1998 and we’ve never seemed to shift back.”
This year, Lake Superior has less than 5% ice cover, and in Thunder Bay in particular, ice is thinner than expected. Small parts of Lake Michigan and Lake Erie have ice cover, and Lake Ontario is largely ice free, while Lake Huron has significantly less ice this year — only 4% coverage in the North Channel and Georgian Bay, as compared to the typical 11%. According to Austin, the long term trend suggests a decline in ice cover of 2-3% per decade, implying a new normal for the Great Lakes. He also studies how seasonal connections to ice impact the environment and various lake populations.
“High ice years tend to be followed by relatively cold summers,” Austin says. “And low ice years like we’re having right now tend to be followed by relatively warm water in the summer. And so one thing I’m working on right now is developing a better understanding of those sorts of connections.”
