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Lake Michigan’s Ice Formations: Part 5

Over the next few days we’ll be posting installments of an ongoing series here at the Backyard Geographer documenting winter ice formation on Lake Michigan.  For previous coverage, see parts 1 and 2 from 2009-2011, and parts 3 and 4 from winter 2012-2013.

PART 5

The following series of pictures was taken on January 22, 2013.  The air temperature on this morning was 8⁰F following several days of below freezing temperatures.  Lake Michigan water temperature is about 37⁰F.

January 22, 2013, looking northeast along lakeshore, Wilmette, Illinois, Langdon Park

January 22, 2013, looking northeast along lakeshore, Wilmette, Illinois, Langdon Park

This picture was taken from the bluff overlooking Lake Michigan in Langdon Park.  Immediately below the bluff is a stretch of frozen sand, then a strip of shore ice varying in width from about 50 to 150 feet, followed by a stretch of open water and breaking waves, and floating ice perhaps ½ mile offshore below the deck of clouds at the horizon. With the water temperature only a few degrees above freezing and the air temperature well below freezing, any water thrown up on the shore solidifies in the air or upon contact with the surface causing the ice to grow out into and over the lake.

January 22, 2013, looking southeast along lakeshore, Wilmette, Illinois (bike for scale)

January 22, 2013, looking southeast along lakeshore, Wilmette, Illinois (bike for scale)

This range of extinct ice volcanoes stretches southward about 50 feet off the sandy shore.  They were formed when the developing ice shelf edge was near this position.  The edge of the ice shelf is about 50 feet further out into the lake now.  As the ice front grows out over the lake, ice volcanoes that were once active become cut off from the supply of water at the liquid/frozen interface.

January 22, 2013, looking into the vent of an extinct ice volcano, Wilmette, Illinois

January 22, 2013, looking into the vent of an extinct ice volcano, Wilmette, Illinois

Here is the view looking down into the vent of one of the extinct ice volcanos in the previous view.  The vent pipe extends down about four feet to a frozen plug.

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January 22, 2013, looking northeast toward Lake Michigan, Wilmette, Illinois

Here is an ice volcano spouting near the edge of the ice shelf.  This active ice volcano is connected to the open water of the lake by an under-ice plumbing system.  Each wave reaching the ice front causes the plumbing system to pressurize, spouting slush into the air.  The slush cools further in the cold air and freezes in place upon contact with the ice front.  If temperatures stay low, the volcano will continue to grow in height and breadth until the ice front advances far enough out into the lake that the plumbing system becomes cut off from its supply of partially-frozen slush.  Each ice volcano sews the seeds of its own extinction as it grows.

January 22, 2013, looking northeast along lakeshore, Wilmette, Illinois (bike for scale)

January 22, 2013, looking northeast along lakeshore, Wilmette, Illinois (bike for scale)

The origin of this this large and level platform of nearly circular plates of ice separated by raised rings of crunchy ice was a mystery to me until I returned the next day to spot a clue. I found similarly sized and shaped ice sheets riding the surf and crashing into the ice front. These also had raised edges, probably from jostling against each other in the swells. Five days later I found similar chunks filling the outer parts of Wilmette harbor.  Perhaps this deposit formed under calm and cold conditions when the floating ice plates froze into a solid mass.

*update* The formations in the picture above are known as pancake ice.  Dimensions of the pancake ice platform estimated to be 250′ x 75′.

text and images by Steve Jansen

Lake Michigan’s Ice Formations: Part 4

Over the next few days we’ll be posting installments of an ongoing series here at the Backyard Geographer documenting winter ice formation on Lake Michigan.  For previous coverage, see parts 1 and 2 from 2009-2011, and part 3 from December of last year.

PART 4

The pictures in the series below were taken on January 11, 2013 after overnight rain. The air temperature was 50⁰F.  Daytime high temperatures have been above freezing for a week.

January 11, 2013, looking northwest along lakeshore, Wilmette, Illinois, Gillson Park

January 11, 2013, looking northwest along lakeshore, Wilmette, Illinois, Gillson Park

By January 11, lakeshore ice has nearly disappeared and Lake Michigan is calm.  It looks much like the scene on December 19 before the first ice of this season formed.

January 11, 2013, looking northwest along lakeshore, Wilmette, Illinois, Gillson Park

January 11, 2013, looking northwest along lakeshore, Wilmette, Illinois, Gillson Park

Only a few small remnants of white remain.  This one runs along the beach for about 30 feet and extends about 10 feet out into Lake Michigan.

January 11, 2013, looking northwest along lakeshore, Wilmette, Illinois, Gillson Park

January 11, 2013, looking northwest along lakeshore, Wilmette, Illinois, Gillson Park

Disguised ice persists in several places.  This slab is so imbedded with sand that it is only revealed by the undercutting action of waves.

January 11, 2013, looking northwest along lakeshore, Wilmette, Illinois, Gillson Park

January 11, 2013, looking northwest along lakeshore, Wilmette, Illinois, Gillson Park

Even as it gives way to warm weather, the shore ice forms fantastical shapes like these delicate stingray figures that seem poised to leap into the lake.

January 11, 2013, looking northwest along lakeshore, Wilmette, Illinois, Gillson Park

January 11, 2013, looking northwest along lakeshore, Wilmette, Illinois, Gillson Park

Eventually all the ice yields and crumples into the lake.

text and images by Steve Jansen

Lake Michigan’s Ice Formations: Part 3

The following post is the third installment of an ongoing series here at the Backyard Geographer documenting seasonal ice formations on Lake Michigan.  For parts 1 and 2, see this post from early last year.

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December 19, 2012, looking northwest along lakeshore, Wilmette, Illinois, Gillson Park

No shore ice this season by December 19.  Compare this to the hundreds of feet of shore ice on this date in 2010 (see photo in Part 2).

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December 29, 2012, looking northwest along lakeshore, Wilmette, Illinois, Gillson Park

Chicago’s record-breaking, 290-day snow drought ended on December 20th but it wasn’t until December 25 that a lake effect event blanketed the lakefront in white. Note that there is still no ice on the lake.

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January 2, 2013, looking northwest along lakeshore, Gillson Park, Wilmette, Illinois

Following the warmest year on record in Chicago, the first shore ice of the season has just formed after an extended period of night temperatures below freezing.  Note that the same narrow band of exposed shore sand shows in this picture as well as in the one above.

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January 2, 2013, looking northwest along lakeshore, Gillson Park, Wilmette, Illinois

This photograph shows the interface where lake ice is freezing to the shore.  The shore ice so far this season is only tens of feet wide compared with hundreds of feet wide in past seasons at this time.

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January 2, 2013, looking northeast toward Lake Michigan, Gillson Park, Wilmette, Illinois

Collections of ice volcanoes are forming in the narrow shelf of shore ice.

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January 2, 2013, looking northeast toward Lake Michigan, Gillson Park, Wilmette, Illinois

Details of one ice volcano and slushy floating ice that help form the ice shelf along the shore are visible.

text and images by Steve Jansen

Mild Winter and Lake Michigan’s Ice Formations

The following post is in two parts. The first part, originally published on the GSC’s website, documents ice formations on Lake Michigan from the winter of 2009-2010, one of the more robust winters in Chicago history.  The second part documents ice formations on the the same patch of lakefront this past January, during what has turned out to be one of the mildest winters on record.  The difference is pretty remarkable.  Click through to see for yourself…

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