Tuesday, February 18, 2014

Record Ice Cover on the Great Lakes

This winter is for the record books. As of last Thursday 88.4 percent of the lakes' total surface area was considered to be ice-covered. This is close to the the all-time high this century of 95 percent, set in February 1979.  Since we still have lots of winter left, it is likely that we could break this record.

The extent of the ice cover for the five Great Lakes as of last week:
— Lake Erie, 95.8 percent.
— Lake Huron, 95.5 percent.
— Lake Superior, 94.6 percent.
— Lake Michigan, 82.3 percent.
— Lake Ontario, 43.4 percent.

The amount of ice coverage depends on many factors.  Certainly the ambient air temperature is key, but also wind, snow, and lake depth affect ice cover.  The minimum and maximum depths of the lakes are:

— Lake Erie, 62 feet / 210 feet.
— Lake Huron, 195 feet / 750 feet.
— Lake Michigan, 279 feet / 925 feet.
— Lake Ontario, 283 feet / 802 feet.
— Lake Superior, 483 feet / 1,332 feet.

The two NASA photos below were taken last week.

The chart below compiled by NOAA shows maximum ice coverage from 1973 through 2013.  Since this year is not yet done accumulating ice, this year's total is not yet included.

Here are a couple photos/charts of Lake Superior.

The other record that has been broken this winter is the number of consecutive days with temperatures below freezing.  The last time the Upper Peninsula saw temperatures above freezing was December 5th.  That is 74 consecutive cold days.  Today will probably end that streak since temps are supposed to rise to the mid-30s.


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