Experts expect Great Lakes water levels to remain high

By: Kevin Bunch | Roseville - Eastpointe Eastsider | Published May 20, 2016

 Water in Lake St. Clair nears the top of a dock at the Blossom Heath Park boat launch in St. Clair Shores May 20.

Water in Lake St. Clair nears the top of a dock at the Blossom Heath Park boat launch in St. Clair Shores May 20.

Photo by Donna Agusti

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METRO DETROIT — Despite a warmer and drier winter than usual, water levels across the Great Lakes — including Lake St. Clair — have remained higher than the long-term average.

What’s more, researchers at the U.S. Army Corps of Engineers and the National Oceanic and Atmospheric Administration expect those high water levels to remain for the coming months.

According to NOAA’s data, in April the Lake Michigan-Huron water system was 579.95 feet high, above the long-term average of 578.8 feet. Lake St. Clair was 575.75 feet, above the 574.18 feet long-term average. Lake Erie was 572.83 feet high, above its long-term average of 571.32 feet.

The NOAA predictions see all lake levels rising during the summer months and peaking around July or August before going into their seasonal drop in the fall. Water levels are measured using benchmarks on the lakes against sea level.

Keith Kompoltowicz, chief hydrologist with the Army Corps of Engineers, said only Lake Superior is below where it was a year ago — the other lakes are all higher than they were last May. Locally, Lake Erie and Lake St. Clair are each a foot higher than they were at this time last year. While the “starkly different” winter may have been an issue for people, its impact on the lake system was fairly limited.

“This winter was quite a bit warmer than the last two, but we saw an interesting month in December when we had quite a bit of rainfall in the Great Lakes,” Kompoltowicz said. “That caused some interesting fluctuations in lake levels from what lakes are typically doing in the November-December time frame. Huron and Michigan rose from November to December for the first time in recorded history as a result of rain falling into the system rather than snow.”

A lack of ice cover like the lakes saw this winter would typically cause a lot of evaporation, as warm water hits cold air, but Kompoltowicz said the above-average temperatures for much of the winter meant that evaporation was minimal, and ultimately the evaporation came out to about the same amount as usual.

Spring, typically the wettest time of the year, usually helps bring water levels up higher, though Kompoltowicz said there are no indications that the region will be getting heavy rains in the coming weeks that could drive water level increases.

After an El Niño event like the one experienced during the winter, there is a good possibility of a La Niña event developing, which would lead to more precipitation and colder temperatures in the fall and winter, but warmer temperatures in the summer.

Kompoltowicz said that if such an event forms, the lakes would see a greater degree of evaporation in the fall, as warmer water temperatures from the summer heat would run up against rapidly cooling air temperatures. That, in turn, would cause water levels to drop.

“A lot is going to happen between now and then, but that’s one possible scenario acting out into the future,” he said.

During NOAA’s monthly climate update May 19, meteorologist and seasonal forecaster Stephen Baxter said the chances of a La Niña forming in late summer have reached 75 percent.

He explained that while an El Niño involves warm water in the Pacific Ocean reaching the surface, a La Niña sees an upswell of cold water reaching the surface. Baxter said the cold water is going fairly deep into the ocean, as opposed to a couple dozen meters down for the warm water related to El Niño.

“All of these point to a developing La Niña,” Baxter said. “Even though an El Niño advisory remains in place, the transition to neutral is well underway … and during the summer we’re expecting a transition to La Niña.”
In both cases, the event causes changes to local weather and climate patterns across the globe; this year’s particularly strong El Niño has driven global temperatures well above the record set by this time last year by more than a degree Celsius globally.

According to NOAA’s data, the summer months currently have a 40 percent chance of being hotter than the long-term average, but there is not enough data to determine whether or not it should be wetter or drier than usual.

Kompoltowicz also wanted to remind people that up until the 2013-14 winter, the Great Lakes were at extremely low levels. A pair of consecutive cold, wet winters followed by wet springs caused the lakes to rebound to where they are today.

“These above-average water levels aren’t necessarily new; we’ve just spent so much time at lower-than-average levels, it’s a different regime we’re in now,” Kompoltowicz said.

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