MUNISING, Mich. (WJMN) – When a group of mountain bikers from Wisconsin decided to take a break and rent a pontoon boat on Saturday, they had no idea what they were about to experience. While erosion of the sandstone cliffs happens regularly at Pictured Rocks National Lakeshore, there are not always people around to see it.

“Some boaters were out enjoying Lake Superior and going along the cliffs. As they say on the video they heard popping and noise. Sand started coming down. First, a little bit and then a nice little section dropped right off into Lake Superior from our Pictured Rocks Cliffs,” said Susan Reece, Chief of Interpretation & Education, Pictured Rocks National Lakeshore.

Reece said the near vertical cliffs are always eroding. With a little help from rain, snow, or ice and some gravity, sections can fall off at any time.

“Down on the water, people want to get close to the rocks. They are really pretty. You can see at the base of the cliffs along there, there are rock piles from previous collapses. So remembering this can happen at any point. Even keeping your ears open like these boaters heard the popping beforehand,” said Reece.

No section of the North Country Trail was affected on the cliffs above. Reece did caution people to be aware of their surroundings.

“People always create social trails. They always want a better view than the one they are getting. So they get closer and closer to the edge. They find that little outcrop sticking out over the lake. So its always taking a risk doing that. Even understanding that our rock is sandstone and is easily eroded and constantly giving away, so people should be aware of that.”

On the boat on Saturday were Jahn Martin and Brad Gustafson of Wisconsin. Martin recorded the video above. Gustafson was in charge of driving the pontoon. Martin shared his account with us of what happened on Saturday.

“We’re just a bunch of Wisconsin mountain bikers coming up to enjoy the trails in Marquette and Munising. We had planned to take a break on Saturday afternoon and rented a pontoon in Munising. We boated up to Pictured Rocks National Lakeshore. On our way back down the shoreline, one of our passengers happened to catch a small bit of random debris falling from one of the cliff faces. What was not captured on video was prior to the event there was a small section about four feet wide that crumbled apart and fell into the water below. So that caught our attention. Brad was driving. He slowed the boat and turned in toward the lakeshore. He got about 100 yards off the lakeshore and then probably within one or two minutes, more debris began to fall across a wider section of the cliff base, about 200 feet wide. You could hear the earth pop and click, almost like muted gunfire, resulting in what you saw on the video which was the collapse of that cliff wall.”

In the video you can hear one of the people on the boat yelling at Gustafson to move the boat.

So why didn’t Brad back up?

“For me this is a pretty unique event. I’m an outdoor enthusiast. I mountain bike all over the upper Midwest. We also do some paddling. I’ve experienced some really glorious things in nature, but I’ve got to say this is a stand alone event.” Martin said.

While this was likely a once-in-a-lifetime event for those on the boat, Martin said this wasn’t their first and won’t be their last visit to enjoy the natural beauty of the U.P.

Martin said, “Brad and I both involved in our local chapter (CWOCC) here in central Wisconsin. For me and others, the Marquette and Munising area is a regular visitation for us to go up and enjoy your trails with the NTN and the Munising Bay Trail Network. You guys have a tremendous asset up there and it’s not just what’s happening on the trails and the water, it’s even the culture of your communities. The restaurants, the brewpubs, the coffee shops, the people, it is really a unique and memorable place to visit.”