Great Lakes Percentage of Ice Cover Dropped

great lakesJust last week reports of record-breaking Great Lakes ice coverage circulated, along with NOAA’s satellite images. A change in weather over the last few days, however, has changed the circumstances and swiftly dropped the percentage of ice cover on the lakes.

Ice coverage had reached close to 90 percent last week. According to NASA, the Great Lakes reached 88 percent ice cover, which is much higher than the average of just 50 percent. NASA used infrared images to see exactly what the lakes were made of and what percentages were ice, clouds or free-standing water.

Coverage of these lakes rarely reaches over 80 percent, and that has only happened five times in the last four decades. The Great Lakes came close to hitting the record set in 1994, thanks to a cold winter that came early. Ice formed on the lakes as early as late November, though it is normal for it to happen in mid-December.

Nathan Kurtz, a scientist at NASA’s Goddard Space Flight Center, blames the high ice coverage this year on cold air that hovered over the Great Lakes most of the season. The arctic air and high winds rob the lakes of their heat. Once they freeze, the ice forms on top. He said that snow, clouds and wind also affect how ice forms on the lakes.

However, there are two silver linings to having the lakes almost completely ice-covered. The first is that winds are not able to blow snow and water over the mainland and create lake effect snow. The second will come this summer as the water levels rise due to limited evaporation.

In a brief reprieve from the harsh winter that the Great Lakes endured this season, the area had sunshine, warmer temps (in the 40s) and high winds. This sudden change in weather conditions had an immediate effect on the ice over the lakes. In fact, the ice cover over the Great Lakes dropped to 69 percent over the course of a few days.

The ice near the Illinois and Wisconsin border is virtually gone. What had been solid ice last week has now drifted off into the lakes or completely melted.

The Great Lakes are no longer at an ice coverage level that is safe to walk on. People are asked to use caution and not venture out on the ice due to the big meltdown that the lakes experienced over the last few days. Lake Michigan ice coverage dropped by 30 percent and went from 70 percent cover to 37 percent. The ice is not nearly as thick as it was just last week.

According to The Weather Channel’s 10-day forecast, winter is far from over in the Great Lakes. Cold temperatures settle back into the area this week. Tuesday’s low is expected to be four below, with a high of 19, followed by several days with a high of 10 degrees.

Although another blast of cold air is expected, it is not enough to get the ice coverage back up to 90 percent on the Great Lakes. Since it is late in the winter season, it is unlikely that the ice cover will get that high again this year.

By Tracy Rose


Fox 17
IB Times
Earth Observatory

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