As we write, the news has just come in about a massive and horrible landslide in Papua New Guinea. At least 2,000 people have died, buried in an earthen slide at the base of a great mountain in the center of the country. Nothing like this can possibly happen in our region but lessor events have long and frequently occurred. We are columnists, not news reporters – most of the time. The exception is with local landslides. We have been watching out for them all during the last quarter century. These are serious news stories and, when they occur, we become news reporters. We like to get out and take a good look as soon as possible. That was the case with the Cauterskill Road landslide that we talked about last week. When we got there, we saw something that we are quite
familiar with – all too familiar with. The back wall of the slide was a nearly vertical cliff. See our photo. Below that was a sizable mass of earth that had suddenly slid downhill during the landside event. That sort of thing is called a compound rotational slump. That back wall of the slump exposed a mix of the dark, fine-grained sand and silt, and we recognized it as being the long-ago deposits of an ice age lake. The slump had reached up so close to the home that it has effectively destroyed it. It’s reported to have been declared as being uninhabitable. We understand that there is a GoFundMe page. Similar slumps have been occurring for thousands of years, up and down the Hudson Valley, wherever glacial lake deposits are found. See our second illustration, courtesy of the New York State Museum. That red zone is where landslides have been concentrated. Yep, that is the Hudson Valley, our valley.
This really is dangerous stuff. We have met people who have lost their homes and we have met people who live with the fear of losing their homes. We actually have had to tell people that their family’s home was in danger. There are two issues we would like to address today. The first is to ask why houses are built in such dangerous locations. The answer is, most of the time, that people don’t know better. Few people understand much about such geohazards. Very few have college degrees in geology; they see the ground beneath them as being solid and stable, even when near the edges of steep slopes. They just can’t imagine that a landslide can come along and cause such a catastrophic collapse. Red lights should be blinking on and off, but they don’t. We have long wanted to help make people aware of these hazards and have written about them extensively but are not convinced that it has sunk in very much. We have long argued that zoning boards should be far more aware of these geohazards than they are. They should never allow new homes or buildings of any sort to be constructed on landslide prone sites. But most of the danger zones that we are aware of were built upon long before modern zoning boards came along.
The second issue involves homeowners’ insurance coverage for landslides. When we moved into our home and got insurance, we asked about landslides. We were told that such insurance was not available. That was because insurance actuaries thought that they could not calculate the hazards. Landslides, they thought, were completely random events. We think that does not have to be. Most landslides, at least in the Hudson Valley, are located on glacial lake deposits and those have been mapped. It should be easy to determine what percent of buildings and homes lie upon lake deposits. And presto – there’s the risk.
In the end we all need to understand the risks of landslides in our Hudson Valley. It’s an important aspect of our culture. Are you in the market to buy a home? Well, read our last two columns again.
Contact the authors at randjtitus@prodigy.net.” Join their facebook page “The Catskill Geologist.” Read their blogs at “thecatskillgeologist.com.”
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