The deadly landslide that killed two children in a St. Paul park raises questions about the stability and safety of the city's iconic bluffs.
Lilydale Regional Park has been closed in the area where two boys died Wednesday as they searched for fossils as part of a school field trip. The closure will last at least two weeks, while the city investigates what caused the landslide and how to make the park safer.
Peggy Lynch was devastated by the landslide, but not surprised. Lynch, executive director of the Friends of the Parks and trails of St. Paul and Ramsey County, said the bluffs, which rise 30 to 40 feet above Lilydale Regional Park's fossil grounds are inherently unstable.
"The bluffs are fragile and with the periods of rain we've had, they just don't hold up" Lynch said.
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• Photos: The deadly Lilydale landeslide
• Story: Park to remain closed after fatal landslide
• Story: School, community copes with tragedy
• Story: Landslide raises questions about bluff's safety
• Interview: What caused the Lilydale landslide?
Any steep slope is prone to erosion. Geologists say the soil of the bluffs is weak. The top layer is sand, and below it is a layer containing clay, which acts as a lubricant. When it's saturated with water, the ground can give way.
Harvey Thorleifson, director of the Minnesota Geological Survey. has gone fossil hunting in the park many times, and says there is evidence of past land slides -- albeit much smaller than this week's tragic event -- all along the bottom of the bluff.
"Well you can see on the site where slabs of rocks and sediment from above have fallen down," Thorleifson said. "That's one of the factors that makes the site attractive to discover fossils that have fallen down."
Thorliefson is working with other geologists and engineers from the Minnesota Department of Natural Resources to determine exactly what caused the landslide. The group will also advise the city on how to make the park safer.
St. Paul officials say there were no signs the land at the top of the bluff was on the verge of collapse. They also say the magnitude of the landslide was unprecedented -- at least in recent memory. The city says there have been no serious accidents in Lilydale Regional Park for the last five years. But outside the park, two miles away along the same Mississippi River bluff, there was a close call a couple years ago.
It was early in the morning on April 8, 2011, when Robert Dubuc arrived at his bakery, which sat right at the base of the bluffs on Wabasha Street. He smelled gas in the air, and went to investigate. Dubuc made his way to the door of a large storage room.
"Finally I pushed the door and stuck my head in there, and it looked like a bomb had gone off, and a boulder the size of two minivans was sitting in the back of the building," Dubuc said.
The city condemned the structure that very night. Dubuc has since relocated the business, Bread, Coffee and Cake, to Mendota Heights. He's glad to be away from the bluffs.
"It's a death zone, basically, and I think that you have to look at it that way," Dubuc said. "With these children, hopefully there will be a serious discussion about finding a solution to these problems so this never, ever happens again. It shouldn't have happened."
For now the section of Lilydale Regional Park where the landslide happened remains closed indefinitely. At a press conference Thursday, St. Paul Mayor Chris Coleman made it clear he wants to reopen the park eventually. Coleman lives at the top of the bluff, right across the street from the park. He goes there all the time, he said.
"I have gone in the rain. I've gone in the sunshine. I've gone in the snow in this place. They're wonderful spaces," Coleman said. "For children to be able to explore and collect fossils or to get an understanding of the science of that area, I think is incredibly important."
Coleman said thousands of school children have explored the park safely over the years, and he wants more to have that opportunity in the future.