RIVERDALE, Utah -- The City of Riverdale plans to drill wells in a neighborhood above a bluff in the coming weeks to help figure out what caused a massive landslide in November that led to the indefinite evacuation of four families.
Chunks of the hill continue to break off, and the Utah Geological Survey said Friday they don't know when it'll stop.
Video from this week shows steady streams of dirt tumbling down the hill behind the house where Gari Manning grew up.
"Oh! Look at that," Manning can be heard saying in the video, as she watches the dirt and sand move in waterfall-like form.
"Standing down there, and watching your home disintegrate before your eyes is pretty startling," she said.
Manning said she's visited the hillside every week since late November when the landslide sparked her mom to quickly evacuate their family's home of 42 years.
It's one of four homes that now sit empty, while the collapsing hillside creeps scarily close to the houses.
"It's up into the developed portion of her yard," Manning explained, of where the broken vertical cliff now sits. She guessed it's 50 feet away from her mother's home.
She's wondered what exactly led to this massive earth movement, and on Wednesday she and her husband noticed the dirt moving as trains on the bottom of the hill barreled by.
She said her mom's been complaining over the past year about more trains passing by at the bottom of the hill, even at times shaking the house.
"I suspect that the trains are an aggravating factor," she said.
You can hear Manning and her husband speculate about it in the video.
"The trains came by and you have two little falloffs," her husband says, as fresh brown dirt falls down the bluff above the trains. "There's a third one. Look at that!"
Greg McDonald with the Utah Geological survey said they've been helping Riverdale City monitor the hill as the city begins to make decisions in how to move forward.
"We're monitoring those right now on, I think, about a weekly basis just to gauge what's happening up on top of the bluff," he explained.
He said groundwater is definitely a contributor to the cause of the slide, and he said they know that the slope geologically, "has had lots of landslides."
But would trains play a role?
"We just don't know. Trains can create ground shaking," he said, but added that, "it would be speculation to say either way."
As they continue to study the hillside, he said they don't know when the land will stop moving, or how close to the houses it'll get.
Riverdale will install groundwater monitoring wells, he said. On Friday, equipment to dig those wells sat on the street in front of Manning's childhood home.
For her and her mother, it's a slow waiting game.
"Dealing with the unknown, being displaced—that's hugely stressful," she said.
Manning said the city has told her they don't know yet if the slide will reach her mother's house, or if it'll end up like the streams of dirt she's been watching crumble down the hillside.