EPOD 20th - Lake Michigan Ice Balls Recurrence
September 27, 2020
We’re celebrating 20 years of Earth Science Picture of the Day during the month of September! Today’s photo features a popular EPOD from the past. Thanks to all of our followers (on the blog, Facebook, Instagram and Twitter) for supporting us. Thanks also to all of you who’ve submitted your photos. We’re most appreciative. This EPOD was originally published February 4, 2014.
Photographer: Ken Scott
Summary Author: Ken Scott 
The photo at top shows a crop of ice balls just deposited from the frigid waters of Lake Michigan during the polar vortex event of January 6-8. These nearly spherical concretions accumulated along Sleeping Bear Dunes National Lakeshore, on the northeastern shore of Lake Michigan. The ones featured here are somewhat smaller than the basketball-sized spheres that blanketed the shore last winter.
Ice balls form where water turbulence breaks up a layer of slush. Click here for animation. Slushy ice mattes and frazil ice accrete in the wind-whipped supercooled water. The mattes eventually form into rounded lumps and will continue to grow until big waves push them on shore or until they end up in a protected inlet - photo at left.
Photo Details: Camera: NIKON D600; Lens: 24.0-85.0 mm f/3.5-4.5; Focal Length: 28.0mm (35mm equivalent: 28mm); Aperture: f/11.0; Exposure Time: 3.000 s; ISO equiv: 800; Software: Photomatix Pro 5.0.
[9/20]ENC11022019