How do you know a storm is really serious? Maybe when it smashes a 20-foot structure into Lake Michigan.

Photographer Ann Barbeau of Manitowoc, Wisconsin told me she enjoys the shore of the Great Lake daily. On Monday, she was out near Manitowoc's South Pier Light Navigational Beacon just as the storm turned fierce.

"I was out this morning taking pictures of the waves," Barbeau said, noting that she was using sports mode on her camera to take multiple photos at once. "This big wave came in, and as soon as it cleared, the light tower was gone."

The series of 16 photos, which Barbeau posted on Facebook and allowed CNET to reproduce here, show a gigantic wave crashing into the 20-foot structure, then hiding it from view. When the waves clear -- like an evil magician's trick, the beacon is gone.

"I looked in the water, and it was floating for about five seconds, then sunk," she said. "I looked around and cleared my eyes because I couldn't believe what I just witnessed."

The stunning crash created multiple emotions for Barbeau, who says she felt, "sad, bad, (and) super-excited at the same time."

Some news reports said that a lighthouse was washed away, and the Manitowoc Breakwater Lighthouse does indeed stand at the end of the city's north pier. But that wasn't what fell into the water, Chief Eric Olson of the US Coast Guard confirmed to Green Bay's WFRV news. The lighthouse still stands.

Instead, it was the nearby beacon that Barbeau saw crash into the lake, a victim of the strong waves and wind that hit its 20-foot-tall fiberglass tower.

"It's an aid to navigation," Olson told WFRV, "but certainly still an important beacon and we'll definitely look to address the fact that it's missing."

The event took place around 8:30 a.m. CT Monday morning, and no one was injured. The Coast Guard did not immediately respond to a CNET request for comment.

Olson told the Manitowoc Herald Times Reporter that the Coast Guard will search for the beacon, and that it does need to be replaced. He also told the paper he's not aware of anything similar happening on the lake in the past.

"Rest In Peace, South Pier Lighthouse," wrote Manitowoc mayor Justin Nickels in a tweet. (He probably meant "beacon," but the hyperbole is understandable.) "We can now add this to our upcoming attractions in our Marine Sanctuary along with the shipwrecks. In all seriousness, the Coast Guard has been notified about this since it is their lighthouse. All will be well."

Olson told WFRV that the beacon will be replaced in the spring, and said the strength of Monday's waves, aided by the direction in which they were crashing, caused the beacon to wash into the lake.

"The waves got very large and the direction was directly into the break wall," he told the station. "It's not a common occurrence, but in the end Mother Nature sometimes wins."

For Barbeau, it was a once-in-a-lifetime lake walk. 

"What a crazy experience!" she wrote on Facebook.

Taking It to Extremes: Mix insane situations -- erupting volcanoes, nuclear meltdowns, 30-foot waves -- with everyday tech. Here's what happens.

Fight the Power: Take a look at who's transforming the way we think about energy.