EVERETT — Jay Himmelman bought his home last summer for its location, the price and the view.

He never imagined the slope behind his house would begin sliding away.

The Everett man and four of his neighbors live on a hillside overlooking the Snohomish River valley. For the last month, they’ve watched the steep bank below their homes rapidly erode.

One family had to abandon their home. Another lost their deck. Back yards along the strip of homes are all at risk of sloughing away.

It’s not clear what’s causing the slide — or when it will stop.

“Obviously, we are concerned,” Himmelman said.

The homes are located along Panaview Boulevard and Burl Place in the Valley View neighborhood.

Monday morning, rain water rushed down the hillside in what’s normally a dry drainage ditch. A few trees down the slope cracked and popped as the ground beneath them shifted.

Kimberlee Lines first noticed a problem a month ago when a fissure opened up in her back yard.

In the past few weeks she said, the crack has widened and the lawn has dropped as much as six feet in places.

The moving ground has taken out part of the wooden fence along her neighbor’s property. Through the gap she can see broken glass and the neighbor’s house tipping off its foundation.

So far, the house she is renting seems OK. Every day she checks for cracks in the foundation.

Meanwhile, the earth “keeps sinking and sinking and sinking,” she said.

City workers put yellow warning tape up around her neighbor’s place. They’ve placed a red “do not enter” tag on the house.

The city began monitoring the slide about a month ago, said Ryan Sass, city engineer.

“The movement has been significant,” Sass said. “It’s picked up the pace in the last week.”

The cause isn’t clear, he said.

Everett, with its many steep slopes and soggy gulches, has its share of landslides, Sass said. Usually, the moving earth doesn’t threaten homes.

City crews will continue to monitor the hillside.

“I’m not seeing any sign of it stopping anytime soon,” he said.

Many landslides occur near areas of recent erosion caused either by water or people, said Bill Schulz, an engineering geologist based in Colorado with the U.S. Geological Survey. By recent, he means in the past 10,000 years.

He’s been a part of a first-of-its-kind study of landslides in the region.

On many landslide-prone hillsides, water from rainfall or snowmelt filters into the ground, increasing groundwater pressure. Those elevated pressures can weaken the soil and trigger slides.

People can make it worse with poor drainage, landscaping or building. Development can make a previously stable hillside prone to problems.

“It’s a gravitational thing,” he said. “If you load up the top of a hillside with more dirt or rock, that can cause a landslide to occur eventually.”

Himmelman, an aerospace engineer, has embarked on his own investigation. He’s examining water lines and drainage in the area, trying to figure out why a house that has stood for 25 years is having problems now.

The hillside has slid at least twice before in the past two decades, he said. This is the first time homes were threatened.

“Part of this is water,” he said. “I’m trying to understand where is it coming from and why now.”

His house was built on pillars sunk deep into the hill. They are designed to hold the foundation in place if the ground lets loose. He’s concerned about the fissure in his backyard. It’s already upended landscape blocks.

Himmelman said one of his neighbors plans to abandon her house because she doesn’t have insurance.

Even people with homeowner’s insurance typically don’t have coverage for damage caused by landslides, said Stephanie Marquis, spokeswoman office of the insurance commissioner.

As with earthquake insurance, homeowners usually must purchase it separately.

Reporter Debra Smith: 425-339-3197 or dsmith@heraldnet.com