Piers were submerged this summer along the Lake Ontario shoreline from Youngstown to the Thousand Islands.
Lake Erie swamped a breakwater in Cleveland and damaged others at Buffalo harbor.
Chicago's beaches were swallowed whole by Lake Michigan.
The Great Lakes are abnormally high. That's unlikely to change anytime soon, the U.S. Army Corps of Engineers said.
That means when the gales of November arrive – whether early or on time – shorelines could be damaged and erosion could be significant, officials cautioned.
"The forecast does show the lakes remaining above average for the next six months," said Keith Kompoltowicz, the chief of watershed hydrology for the Corps of Engineers' Detroit District, during a conference call with reporters from across the Great Lakes on Tuesday.
Although the water has finally started receding as it normally does during the late summer and fall, some of the highest fall and winter season water levels on record are possible on Lake Erie and Lake Ontario over the next several months.
Experts cite a number of factors behind the record water levels: above-average precipitation over the last six to seven years — with more recent surges in available water caused by melting from last winter's snow pack across the Great Lakes basin; saturated soil from last fall; and an unusually wet spring.
"It really got all those factors combining for rises this spring," Kompoltowicz said.
Just six years removed from a streak of unusually low water levels, Lake Erie broke records for its highest mean monthly water levels in May, June and July.
It is expected to follow suit in August. In June, Lake Erie crested to its highest level since data started being recorded 101 years ago.
Lake Ontario reached its highest average monthly water level in June and July.
Though water levels are starting recede, data shows that Lake Erie's water level remains about 29 inches above its long-term average for August. Lake Ontario's water level is 26 inches above its long-term average.
Strong autumnal storms often bring high winds, which drive heavy waves and threats of shoreline erosion and flooding.
That may be exacerbated this year. And Lake Erie could be the most vulnerable, officials said.
"Lake Erie has the greatest chance for a significant wind set-up," said Lt. Col. Gregory E. Turner of the Corps of Engineers Detroit District.
November gales often drive southwesterly winds, creating a seiche on the lake's eastern end near Buffalo with water rises of 8 feet or more.
"Our breakwaters have taken a significant amount of damage because they're aged and because of the wind and ice, they take a lot of abuse," said Andrew Kornacki, spokesman for the Corps of Engineers in Buffalo.
The shoreline spots most prone to impacts from high wind and rising waters in Erie County include the seawall at Athol Springs, breakwaters on Buffalo's Outer Harbor and the seawalls at LaSalle and Broderick parks in Buffalo, Kornacki said.
Repairs are being made at the breakwaters in Buffalo Harbor.
The Corps of Engineers is expected to begin construction on its more than $8 million project to build a quarter-mile long revetment at Athol Springs in early fall. Plans are also being refined or developed to fix problems at LaSalle and Broderick parks.
Meanwhile, property owners along Lake Erie and Lake Ontario shorelines that are traditionally affected by wind-driven waves during fall and winter storms were advised to brace themselves for the upcoming season.
"We urge lakeshore residents and visitors to be prepared for these events," Kompoltowicz said.