Superior’s frozen splendor
Lake’s ice cover already surpasses predictions for 2018
By CECILIA BROWN
Journal Staff Writer
MARQUETTE — Area residents may have noticed that bitterly cold, snowless days with an unusual amount of sunshine have been a common feature of the past week.
Strangely enough, the root cause of the sunshine and lack of snow is Lake Superior’s increasing ice coverage during the early weeks of February, a result of the recent wave of cold weather.
The sub-normal temperatures of early February have provided a “perfect setup… that’s been (a) big trigger for ice expansion,” said Matt Zika, warning coordination meteorologist at the National Weather Service office in Marquette. “If we do have significant ice growth and ice coverage on the lake, it shuts down the lake-effect snow process.”
He explained that increasing ice coverage on the lake is analogous to putting a lid over a pot of boiling water, as the ice cover limits the amount of water evaporating into the atmosphere from the lake.
Less evaporating lake water means less moisture will rise into the air, which decreases the amount and possibility of lake effect snow and cloud cover in the area.
This explains all of the sunshine recently — there has been a dramatic increase in Lake Superior’s ice coverage since January when the ice coverage on the lake rarely exceeded 20 percent according to data from National Oceanic and Atmospheric Administration’s Great Lakes Environmental Research Laboratory.
On Monday, the average ice coverage on Lake Superior was around 46 percent, which is far over the 25 to 30 percent average for early February, according to GLERL. Most of the ice coverage was concentrated at the shorelines, with average ice thickness across the lake at just over 3 inches and large sections in the eastern portion of the lake with little-to-no ice cover.
By late Friday, over 65 percent of the lake was covered in ice. The average thickness of the lake’s ice had increased to five inches, with thin ice beginning to develop in the previously unfrozen eastern section of the lake.
On Saturday afternoon, the ice coverage on Lake Superior had reached nearly 70 percent, already exceeding the predicted maximum ice coverage of 68 percent for the lake in 2018. Average ice coverage on the lake is predicted to hit 80 percent by Monday.
However, the region is predicted to face warmer temperatures in the coming week, with the ice coverage predicted to plateau around 80 percent early this week, then decline nearly 10 percent by Thursday.
In addition to the warmer temperatures, windstorms can also lead to decreased ice coverage, as much of the lake’s ice isn’t very thick and wind can cause thin ice to shift and break up, Zika said.
Lake Superior’s ice coverage typically peaks between the end of February and early March, according to the website.
“We’re on target for maximum ice coverage to occur over the next two-to-three week time period,” Zika said.
Lake Superior is also seeing much more ice than it has in the two past years. The lake only had around five percent ice coverage at this point in 2017 and just three percent at this point during 2016.
Residents may wonder if they’re in for a repeat of winter 2013-14, which Zika said was a “historically cold winter,” with the thickest ice Lake Superior has seen in a “long, long time.”
Zika said that while ice and cold conditions may seem dramatic compared to recent winters, it likely won’t be a repeat of the winter of 2013-14.
“It’s been cold this year, but it’s not historical by any stretch,” he said. “The setup this year isn’t like those past years where we had thick ice covering most of the lake … we just haven’t been cold enough for a long enough period for the lake to (completely) freeze over.”
Although the lake reached about 95 percent ice coverage during winters 2013-14 and 2014-15, Zika said it is rare for Lake Superior to be completely frozen over, noting a complete freeze-over event usually happens once a decade, on average.
Even though this year’s ice coverage may not be historical and there is much variation in year-to-year ice coverage on Lake Superior, the predicted 80 percent ice coverage for Monday is double the long-time annual average of 40 percent ice coverage by that date.
While people may feel more confident about going out on Lake Superior’s ice due to the cold temperatures and increased ice thickness, it is still of critical importance to exercise the utmost caution when venturing out on the ice.
Ice thickness can vary greatly throughout the lake and as wind speed and direction change, ice shifts around in the lake, which can create dangerous situations, especially in areas with thinner ice, Zika said.
Even if ice appears to be thick and strong, this appearance may be deceptive, as ice is not of uniform thickness and underwater currents can wear thin spots in the ice, according to the Michigan Department of Natural Resource’s website. Ice thickness should be assessed regularly with a spud and ruler for each couple of steps taken on the ice.
Furthermore, ice with slush or snow on it should always be presumed unsafe, as this can indicate the ice beneath may not be completely frozen. Those who go out on the ice should always make sure to carry a cell phone and tell others when and where they are going in case of emergency.
In the event of falling through the ice, the Michigan DNR urges individuals to first remain calm and keep their winter clothing on for warmth and floatation. Then, they should turn in the water towards the direction they came from, as it is probably the strongest ice. If ice picks are available, the DNR recommends digging them into the ice and vigorously kicking, pulling up on to the ice’s surface by sliding forward on the ice. Once on the ice’s surface, the DNR recommends rolling away from the weak ice area, as this will distribute weight across a larger area, reducing the possibility of breaking through the ice again.
Cecilia Brown can be reached at 906-228-2500, ext. 248. Her email address is firstname.lastname@example.org.