Updated: 10/14/2023
Sinkholes Popping Up In Palmyra & Lebanon An Ongoing Problem
Within Palmyra and Lebanon county there have been a large number of sinkholes appearing over the past few years. While historically Palmyra is known for sinkholes it seems like their frequency has increased.
Sinkholes have closed roadways down as well as caused major damage to the foundation of homes in the Palmyra area. What is causing all of these sinkholes and what can be done to manage them and the damage they cause?
What Is A Sinkhole?
A sinkhole is a dip, depression, or hole in the ground caused by the collapse of a surface layer. When a surface layer collapses, it leaves a dip or hole in the earth known as a sinkhole. They come in a variety of sizes and can reach depths of hundreds of feet or only a few feet. Sinkholes may develop gradually over time or unexpectedly. There are many different geological processes that can lead to the creation of sinkholes, and Lebanon County is no exception to this rule.
What Causes Sinkholes In Palmyra Pennsylvania?
The first cause of sinkholes in Palmyra, PA is what is under the ground. The foundation that is found throughout Pennsylvania consists of soil and stone that can easily be dissolved by water. Once the water erodes away from the ground it will eventually collapse and a sinkhole will form.
There are three types of sinkholes that can develop in Palmyra:
- Solution Sinkholes: The area is exposed and progressively erodes away as it is exposed to the rain and water. This can occur quickly or slowly
- Cover Collapse Sinkholes: These are the types of sinkholes that make the news. Suddenly the land or cover collapses into a hole exposing the gaping cavern below. A sinkhole that collapses typically shows sudden danger while the others are progressive and visible.
- Cover Subsidence Sinkholes: This type of sinkhole is a cross between the first two. Small collapses occur as the ground dissolves and erode away.
Palmyra is on top of a large limestone deposits. This limestone dissolves and erodes away easily from the rain. Due to this, the sinkholes are to be expected, but why has their frequency increased?
Why Sinkholes Appear In Lebanon County
There are several causes for sinkholes in Lebanon County, but the following are the most frequent ones:
- Water Infiltration: As water seeps through the soil, it picks up microscopic pieces of rock and transports them away, progressively increasing subterranean caverns. Sinkholes may form as a result of the roofs of these cavities weakening and collapsing over time.
- Human Activity & Construction: Changes in land use and urban development can alter the way water naturally drains and increase water infiltration, which has the effect of hastening the creation of sinkholes. The problem can be made worse by practices including mining, building, and stormwater runoff management.
- Heavy Rainfall & Flooding: Heavy or persistent rain can saturate the earth, adding weight to subsurface spaces and speeding up their collapse. This is especially important in areas like Lebanon County that have seen frequent periods of high rains.
Flooding’s Impact On Sinkholes In Palmyra PA
In some of our recent articles about flooding, we have shared how flood zones have changed in the county of Lebanon. The flood zones have changed and been updated due to a larger amount of areas being susceptible to flooding. This directly impacts the number of sinkholes appearing.
As water sits or is forced to different locations from development and growth in the area, there is a higher likelihood of sinkholes forming. While the amount of water might not increase, the amount of water over specific areas has increased. The flooding changes result in increases in erosion.
Long Term Effects Of Sinkholes In Palmyra
In Palmyra, you can expect sinkholes to continue and increase in frequency. As they continue, the cost for sinkhole insurance could increase based on your location at the epicenter of dissolving limestone. Taxes will probably increase to maintain the infrastructure of the area, specifically repairing Route 422 and other roadways that have sinkholes.
How To Know Where Sinkholes Are Located In Pennsylvania?
Sinkholes can develop anywhere so how do I know if my house is at risk? Lucky for you there are resources and a few different maps and tools that will allow you to know what level of risk you are at.
1. PA Government & The Bureau Of Geological Survey
The first of these tools is from the PA government and the Bureau of Geological Survey. They have a map that they update and manage so you can see how close sinkholes are to your home. Take some time and play around. Zoom in on your PA hometown and see if you are at risk. Make sure to look in the area you are located and be aware of any sinkhole risk factors.
Take a look at their interactive map of Sinkholes in Pennsylvania.
2. ARCGIS Map Of Sinkhole Risk
This map is less detailed but provides a quicker look into the different Risk areas. Zoom in and see where your house is and if you are at risk. View the ARCGIS sinkhole map here.
There is a simple key to the colors on the map:
- Yellow: Low Risk – Carbonate Formations are present, but there are no identified karst Features. Krast Features are at a density of 1 per square mile.
- Orange: Moderate risk – Carbonate formation is present with a density of karst features between 1 and 100 per sq mile
- Red: High Risk – Carbonate Formations are present with a density of karst features over 100 features per sq mile.
These tools can help you understand your own risk and if you live in an at-risk area. It is important to know where you live and how you can protect yourself if you are. Take a look below to learn how you can protect your PA home from sinkholes
How Can You Protect Your Home From Sinkholes
The first and most important step to protecting your home from sinkholes is getting sinkhole insurance. “Oh don’t worry, I have home insurance so my house is safe.” Homeowners’ insurance doesn’t cover sinkhole insurance. Sinkhole insurance is a separate coverage you have to add to your home. Make sure you have coverage on your home for sinkhole damage.
Lowering The Impact Of Sinkholes In Palmyra & Lebanon County
Lebanon County takes a number of steps to lessen the effects of sinkholes since they can endanger property and public safety. To reduce soil erosion and water infiltration, this involves undertaking geological evaluations before to construction, monitoring groundwater levels, and putting stormwater management strategies into operation.
Sinkholes may easily arise in Lebanon County, Pennsylvania, according to its distinctive geology. Residents and local officials must understand the geological processes involved and the regional variables influencing sinkhole formation. Despite the fact that sinkholes are a common occurrence, good land management practices and preventative measures may assist in lessening their effects and guarantee the citizens of the county’s safety and wellbeing.
Contact Strickler Insurance For Sinkhole Insurance
Get a free quote on sinkhole insurance from a local insurance company that can handle your needs effectively. Our team is ready to assess your home and home insurance needs. If you are in an area susceptible to sinkholes we will recommend sinkhole insurance to protect your home from future sinkholes. Learn more today.
