2021 Drought Drains Lake Superior Of Water Level Advances
It was good while it lasted. Add one more thing that this summers drought has affected: Lake Superior water levels. As of August 1, researchers reported that the water in Lake Superior "was only 1.2 inches higher than the 102-year average for this time of year".
The fact that our drier-than-usual conditions have lowered water levels in the largest Great Lake should come as no surprise - but the fact that it comes just two years after record-highs does. Current levels sit 12.2 inches below that record-setting high reported on August 1, 2019. News source also show an obvious decrease from last years level; our numbers for this summer are 9.1 inches below last years levels.
While there had been some concern about water levels in Lake Superior a decade or so ago, the most-recent stretch of five years or so had seen advances made. In the lead up to that record setting summer of 2019, both 2017 and 2018 saw slow, steady water level increases. The U.S. Army Corps of Engineers measured advances of a couple of inches each of the summers; those advances are significant when looked at the overall volume of water contained in Lake Superior:
"Two inches may not seem like a big deal, but it is when we are talking about the world's largest fresh water lake by surface area. Those two inches of water are around 1.1 trillion gallons."
2021's downturn in water levels came pretty quick and pretty significantly. Especially troubling is that the decrease came when legacy timelines usually see an increase. An article in the Superior Telegram shared:
"[t]he International Lake Superior Board of Control reports that continued dry conditions, including drought conditions in Northeastern Minnesota, saw the lake make a highly unusual decline in July, dropping nearly a half-inch in a month that it averages a 2-inch rise."
In contrast to Lake Superior's woes, other Great Lakes seem to be fairing better. Lake Huron and Lake Michigan have seen advances; "the lakes...[rose] 1.6 inches in July, a month they usually rise about a half inch." Both Huron and Michigan currently "sit 16.5 inches below the August 1, 2020 level, but are still 16.9 inches above average". In other words, they're holding their own.