Climate Change Means More Landslides In Pittsburgh's Future

May 10, 2018

In Spring Hill, early 20th Century houses look out over cinematic views of downtown Pittsburgh. The front of 36-year-old resident Randal Miller’s home appears fine, but the back is a mess. Part of it was slammed by a landslide this February.

“The door broke in the first day,” he said. “It didn’t break in in a way that like you could move it, cause there’s like trees sticking through.”

Miller’s laundry room sustained the worst of the damage. Reddish mud and glass cake the floor and everything smell likes mildew.

Randal Miller's laundry room has been covered in mud and glass since mid-February landslides.
Credit Sarah Boden / 90.5 WESA

“About a week later, the second wave of heavy stuff came down and busted this window and pushed the wall in,” he said.

Landslides have always been an issue for the city due to its steep hills, clay soil and narrow valleys, but they usually occur in late spring and early early summer. Winter is typically Pittsburgh’s driest period, which is good, because the soil at that time is very wet as plants have yet to sprout and pull water from the ground.

However, 2018 has been Pittsburgh’s wettest start to the year on record. February in particular was exceptionally rainy with higher than average higher temperatures.

“When we see an incredibly wet February like we had, that’s superimposed on soils that are already wet, and that sort of put in motion a whole sequence of damaging landslides,” said Francis Ashland of the U.S. Geological Survey.

Mid-February landslides damaged a number of homes in Pittsburgh, including Randal Miller's in the Spring Hill neighborhood.
Credit Sarah Boden / 90.5 WESA

In addition to the city’s rivers flooding roads and Point State Park, landslide after landslide has shut down Route 30 and forced people like Miller from their homes.

Ashland said, according to the unofficial historic record, the last time it rained this much during a February was 1891. But in the coming years, February landslides might be more common due to the warming of the earth's climate.

Temperatures in western Pennsylvania are about a degree centigrade warmer, or nearly 2 degrees Fahrenheit, compared to a century ago. Neil Donahue, an atmospheric chemist at Carnegie Mellon University, grew up in Pittsburgh and said he remembers when winters were colder.

“I used to go skating and play ice hockey on a public pond in Fox Chapel when I was a kid,” he said. “You can’t do that anymore. You just plop right into the water.”

Climate change models show that not only is it getting warmer, but weather patterns are becoming more extreme. That means wet places are getting wetter and dry places drier. More water evaporates in warmer temperatures, and warmer air can in turn hold more water creating the potential for heavier storms.

“Pittsburgh is reasonably humid, we get a fair amount of rain,” said Donahue. “The tendency to kind of drizzle may see a bit of a transition to more extreme rainfalls, so more heavy rainfall events.”

There are things the city can do to adapt to the changing climate. One way is capture and divert heavy rain through green infrastructure.

“The basic idea is to use nature as a means both slowing, storing and treating this storm water,” said Jordan Fischbach, co-director of the Rand Corporation’s Water and Climate Resilience Center.

The aftermath of the landslide along Route 30 in East Pittsburgh. The road will be closed for several months and several apartment buildings were destroyed by the landslide.
Credit GOVERNOR TOM WOLF / Flickr

The city is already doing some of this by landscaping native plants and placing rocks in strategic areas. It's also gathering information about soil conditions and storm water drainage to identify the vulnerable areas

Fischbach said officials should also focus on preparedness.

“Making sure that we have alternate transportation routes,” he said. “That emergency vehicles can get through in other ways if we do have a key street, or key bridge that goes out because of a landslide.”         

Back in Spring Hill, Randal Miller said he probably won’t be able to move home until September because the ground is still moving. He pointed to a neighbor’s home more than 100 feet up the hill.

“You know, the big threat at this point is whether or not his house will fall down,” said Miller.

Hopefully, that house doesn’t fall and take Miller’s with it. Landslides aren’t covered in his homeowner’s insurance policy.