Understanding ice safety and accumulation in the Great Lakes

ST. JOSEPH, Mi. -- Under the recent period of colder air advecting from the North Pole, shorelines along every Great Lake experienced notable ice accumulation.

Lake Erie jumped from 5% ice coverage to 21% in just 10 days from January 15-25.

While Lake Michigan did not make as substantial a jump, the lake still saw a seven percent increase to just under 11% over the same 10 days as Lake Erie. 

Historically as of January 26 (when this article was written), about 20% of Lake Michigan is covered by ice according to the Great Lakes Environmental Research Laboratory (GLERL). 

A number of reasons exist for the shortage of sea ice this year within the lakes, most notably the mild temperatures brought on by a strong and persistent El Niño pattern.

The lack of sea ice in Lake Michigan and other Great Lakes also exerts a considerable influence on local forecasts, particularly in lake effect snow events. 

With less sea ice, more sunlight and heat can be absorbed by the darker-colored lake water (see "albedo"), producing more warm and moist air that rises and interacts with the colder air mass aloft.

The more environmental mixing that occurs between colder, northerly winds and warm, moist lake water, the higher chances become for significant lake effect events similar to the one on January 19-20 of this year.

What little ice is present along Lake Michigan likely is not safe to walk or fish on as well.

Ice thickness should be greater than 2" before a person should walk on the frozen surface.

While Lake Michigan has fallen short on ice coverage so far, it is important to note that max ice coverage usually occurs in late February and early March when lake sea surface temperatures are at their coldest.