Great Lakes undergo incredible transformation in less than 1 month
Tourists admiring a glacier in Iceland had to flee on March 31 after big slabs of ice collapsed triggering a large wave. About a dozen people were observing the Breiðamerkurjökull glacier, part of Jökulsárlón glacial lagoon in southeast Iceland, when chunks fell in the water below creating a large wave rushing towards the shore. All the tourists appear to have made it to safety and no one was reported injured. Read more: https://www.accuweather.com/en/weather-news/massive-glacier-collapse-sends-tourists-fleeing-at-famous-lagoon-in-iceland/70007865
January’s polar vortex ushered subzero temperatures across the Midwest and Northeast and was the tipping point that transformed the Great Lakes into a frozen icescape. However, the Great Lakes no longer resemble what they did just a few short weeks ago.
Every winter, frigid Arctic air chills the northern United States, causing ice to form on the Great Lakes. The extent of this ice depends on several variables, including the frequency and duration of Arctic intrusions.
Old Man Winter held a tight grip across the region throughout much of this past winter, causing the ice coverage on the Great Lakes to reach levels not seen since 2015.
A view of the Great Lakes three days after reaching peak ice coverage. Some ice had melted in those three days, but most of Lake Erie and Lake Superior remain covered in ice. (Image/NASA/MODIS/Aqua)
A rapid freezing of the Great Lakes occurred during the record-breaking polar vortex in late January. The most dramatic change took place on Lake Erie where ice coverage spiked from near 20% to near 90% in just a matter of days.
Reinforcing shots of frigid air resulted in more and more ice to freeze-over the lakes, eventually reaching its peak on March 9, 2019.
At its peak, nearly 81% of the lakes were covered in ice, including nearly all of Lake Superior, Lake Huron and Lake Erie. This is significantly higher than the long-term average of 55%, according to the Great Lakes Environmental Research Laboratory (GLERL).
It is also higher than peak ice coverage of 69% in 2018, and drastically higher than the peak ice coverage in 2017, which was 19.4%.
However, by April 1, the ice coverage had plummeted to a mere 15%.
A cloud-free view of the Great Lakes from space, taken on March 25, 2019. (Photo/NASA/MODIS/Terra)
The rapid icemelt was caused by the changing of the season, as milder air returned to the Midwest and the stronger spring sunlight shined longer and more directly at the region.
Most of the ice that does remain sits in the shallows of Lake Superior, Lake Huron, Lake Michigan and the eastern corner of Lake Erie.
The sharp decrease in ice signals more than just a change in the lakes’ appearance.
The shipping season is now officially underway as the lack of ice permits vessels to navigate the largely ice-free waters of the Great Lakes.
On March 22, the first ship of the season left Twin Ports in Duluth, Minnesota, the largest and farthest-inland freshwater port in the world.
Just three days later, the Soo Locks opened, the gateway between Lake Superior and Lake Huron.
“Arriving just in time for the midnight opening of the Poe Lock, the 1,000-foot long Stewart J. Cort officially kicked off the start of the 2019 navigation season at the Soo Locks,” the U.S. Army Corps of Engineers (Detroit District) said in a Facebook post.
This is crucial for the commerce across the regions, such as the steel mill industry, that relies on ships to transport good and materials across the lakes.
Water levels on the Great Lakes are running above average and with ice still covering parts of the lakes, the additional ice melt can cause the water levels to remain heightened into the summer.
“In a severe ice-cover year, the thermal structure of the lakes could be impacted for the rest of the year, potentially reducing evaporation from the lakes next fall. Evaporation and precipitation are the major drivers of seasonal water level changes in the Great Lakes,” GLERL said.
This translates to a greater risk of coastal flooding along the lakeshores over the next several months.
In addition to bringing the risk of flooding, this can have implications on the weather, including temperatures, near the lakes down the road.
“Ice extent plays a part in determining water temperature in the lakes later in the year, as incoming heat will have to melt the ice before it warms the water below,” the GLERL added.
The longer the water in the Great Lakes remains cold, the longer it will delay the yearly algae blooms in the summer. This is particularly a problem on Lake Erie where these algae blooms can become toxic, polluting drinking water and harming the environment.
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