VIIRS Imagery shows ice cover on Great Lakes

February 20th, 2021 |

Suomi-NPP VIIRS true-color imagery (1843 UTC) and GOES-16 Band 5 (1.61 µm) imagery (1841 UTC) on 20 February 2021 (Click to enlarge)

An uncommon somewhat clear day on 20 February 2021 allowed VIIRS on Suomi-NPP to provide a true-color image of all 5 Great Lakes. The true-color image above is shown in a toggle with GOES-16 “Snow-Ice” Band 5 near-infrared data (1.61 µm) that allows for discrimination between clouds made up of water droplets (bright white) and underlying snow/ice (darker grey).  Much of western Lake Superior shows ice:  highly reflective in the true color imagery and much darker in the snow/ice channel (but not quite as dark as open water).  Lake Superior has about 50% ice coverage (this figure, originally from this website).  Western Lake Michigan shows little ice coverage (except over Green Bay);  ice coverage on Michigan is less than 30%.   Lake Erie is the most ice-covered of the Lakes:  around 80% ice-covered.  Recent northwesterly winds have moved the pack ice away from the northern shore (except for the far western basin).