Landslides risk in Maryland

Landslide Characteristics in Maryland

Maryland's landslide risk is generally low, but certain regions are more susceptible due to their topography and geology. The state's landscape varies from the flat coastal plains of the Eastern Shore to the rolling hills of central Maryland and the steep, mountainous terrain of western Maryland. The Appalachian Plateau and Valley and Ridge provinces in western Maryland, including areas around Cumberland, Frostburg, and the Deep Creek Lake region, have the highest potential for landslides. Additionally, steep bluffs along the Potomac River and the Chesapeake Bay, as well as some areas in the Piedmont region, can experience slope failures.

Landslides in Maryland are typically triggered by intense or prolonged rainfall, rapid snowmelt, and freeze-thaw cycles. The most common types are shallow debris flows, rockfalls, and slumps. These events often occur during heavy rainstorms, hurricanes, or nor'easters, and in late winter or early spring when snowmelt saturates the ground. Human activities such as excavation, construction on slopes, and improper drainage can also increase landslide risk.

While Maryland does not experience the frequent, large-scale landslides seen in California or the Pacific Northwest, localized events can still cause significant damage. The Maryland Department of Emergency Management (MDEM) and the USGS Landslide Hazards Program provide resources to help residents understand and mitigate this risk.

How It Affects Homes

Landslides can cause severe damage to homes and property. Even a small slide can crack foundations, shift walls, break windows, and damage decks, driveways, and septic systems. Mudflows and debris flows can inundate lower levels, while rockfalls can strike structures directly. In Maryland, where landslides are often shallow and localized, the primary risks are to homes built on or near steep slopes, at the base of slopes, or in areas with poor drainage.

Standard homeowners insurance policies typically do not cover landslide damage. Most policies exclude earth movement, which includes landslides, mudslides, and sinkholes. Some insurers offer endorsements or separate policies for landslide coverage, but these are not common in Maryland due to the relatively low risk. FEMA's National Flood Insurance Program (NFIP) does not cover landslides either, though it may cover mudflows if they meet certain criteria. If a landslide is declared a federal disaster, FEMA may provide individual assistance grants, but these are not a substitute for insurance. Homeowners should review their policies and consider whether additional coverage is available or necessary. Ready.gov offers guidance on preparing for landslides and understanding insurance options.

How to Prepare Your Home

While Maryland's landslide risk is low, homeowners in susceptible areas can take steps to reduce their risk:

• Assess your property: Look for signs of slope instability such as cracks in the soil, leaning trees or utility poles, doors or windows that stick, or previous landslide scars. If you notice these signs, consult a geotechnical engineer or engineering geologist.
• Manage water: Proper drainage is critical. Ensure gutters and downspouts direct water away from slopes and foundations. Avoid overwatering lawns on slopes, and repair any leaking pipes or septic systems promptly.
• Maintain vegetation: Deep-rooted plants and trees can help stabilize slopes. Avoid removing vegetation from steep slopes, and consult a professional before planting or clearing.
• Avoid altering slopes: Do not cut into slopes or add fill without professional advice. Excavation can remove support at the toe of a slope, and adding weight at the top can increase instability.
• Install retaining walls: If appropriate, engineered retaining walls can help hold back soil. These must be designed by a qualified professional and properly drained.
• Create an evacuation plan: Know the warning signs of a landslide (such as sudden changes in water flow or rumbling sounds) and have a plan to evacuate quickly. Contact your local emergency management office for guidance.
• Consider insurance: Check with your insurance agent about available coverage for landslides or earth movement. While standard policies exclude it, you may be able to purchase additional coverage.

Frequently Asked Questions

Does Maryland have a high risk of landslides?

No, Maryland is generally considered to have a low risk of landslides compared to states like California, Oregon, or West Virginia. However, localized landslides can and do occur, particularly in the western mountainous regions and along steep river bluffs. The Maryland Department of Emergency Management rates the statewide risk as level 1 out of 5.

What areas in Maryland are most prone to landslides?

The most susceptible areas are in western Maryland, including the Appalachian Plateau and Valley and Ridge provinces (e.g., Allegany, Garrett, and Washington counties). Steep slopes along the Potomac River, the Chesapeake Bay bluffs, and some parts of the Piedmont region can also experience landslides, especially after heavy rainfall or snowmelt.

Does homeowners insurance cover landslide damage?

Standard homeowners insurance policies typically exclude landslide and other earth movement damage. Some insurers may offer a separate endorsement or policy for landslide coverage, but availability varies. FEMA disaster assistance may help if a presidential disaster declaration is made, but it is not guaranteed. Homeowners should review their policy and discuss options with their insurance agent.

Official Resources

• Maryland Department of Emergency Management
• USGS Landslide Hazards Program
• Ready.gov – Landslides and Debris Flow