Landslides risk in Vermont

Landslide risk in Vermont: steep slopes, clay soils, and wet seasons

Vermont is not a state most people associate with landslides, but the same geology and weather that make it scenic also make its hillsides vulnerable. Glaciers shaped much of the state, leaving steep mountain slopes, narrow river valleys, and — in the Champlain Valley — thick beds of sensitive marine clay deposited when the Champlain Sea covered the region thousands of years ago. Each of these settings fails in a different way, and each creates different risks for the homes built on or near it.

Landslides in Vermont generally take one of four forms:

• Shallow debris slides and debris flows on steep, soil-covered slopes in the Green Mountains and other uplands, often during or shortly after intense rainfall.
• Slumps and earthflows in clay along Lake Champlain bluffs and riverbanks, where saturated clay loses strength and large blocks of ground creep or slide downhill.
• Rockfall from ledges, cliffs, and road cuts, especially during freeze-thaw cycles in late winter and early spring.
• Streambank collapse, where high water undercuts banks and carries away yards, driveways, and sometimes structures.

Timing matters. The highest-risk windows in Vermont are spring snowmelt, when soils are saturated and streams run high; the summer and early fall thunderstorm season; and any period when the remnants of a tropical storm cross the state. Tropical Storm Irene in 2011 triggered hundreds of landslides and debris flows across Vermont, damaging roads and homes, and heavy rain events since then have repeatedly caused slope failures and washouts. Winter freeze-thaw also loosens rock on steep slopes and cuts.

The most exposed locations include the steep slopes of the Green Mountains and the Northeast Kingdom, narrow valleys and stream corridors (the Winooski, Lamoille, Mad, and White River watersheds among them), the Lake Champlain shoreline bluffs in Chittenden, Addison, and Grand Isle counties, and mountain road corridors where cut slopes and fill slopes give way. Homes built on or directly below a steep slope, at the edge of a bluff, or close to an eroding stream bank face the greatest risk, and the hazard is often concentrated in ways that a statewide rating cannot capture.

How it affects homes

Landslide damage to Vermont homes ranges from slow, subtle movement to sudden and destructive failure. On clay bluffs and gentle hillsides, ground movement can continue for months, showing up first as cracks in foundations and interior walls, doors and windows that stop closing properly, and floors that go out of level. On steeper slopes, failure is often abrupt: a debris slide or flow can strike a house, fill it with mud, rock, and water, and tear away decks, porches, and additions.

Common property impacts include:

• Cracked, bowed, or displaced foundations and retaining walls
• Sheared water, sewer, and septic lines, and damaged wells
• Loss of driveways, access roads, and culverts, which can leave a home unreachable
• Toppled trees, downed power lines, and debris striking the structure
• Loss of usable land, including yards, gardens, and septic disposal areas
• Displaced propane tanks and other fuel hazards

On insurance, the key point for Vermont homeowners is that standard homeowners policies typically exclude earth movement, which includes landslide and slope failure. Flood insurance purchased through the National Flood Insurance Program covers mudflow — defined as a river of liquid and flowing mud — but not landslide or general earth movement. Some private carriers offer limited endorsements or surplus-lines policies for specific slope situations, so it is worth asking a licensed Vermont agent what, if anything, is available for your property. Documenting the condition of your home with dated photos and keeping receipts for any mitigation work will help if you ever need to file a claim or apply for federal disaster assistance after a presidentially declared event.

How to prepare your home

Because landslide insurance is limited, reducing the risk in the first place is the most effective protection:

1. Learn your slope. Note whether your home sits below a steep hillside, on fill, or at the top of a bluff or stream bank. Watch for new cracks, tilted trees and utility poles, soil bulges at the base of a slope, and springs or seeps that appear after storms.
2. Manage water. Keep gutters and downspouts clear, and discharge roof water well away from slopes and foundations. Avoid concentrating runoff onto a hillside, and never discharge a sump pump onto a steep slope.
3. Do not add weight at the top or remove support at the bottom. Pools, sheds, fills, and large structures placed near the crest of a slope can trigger failure, and excavating at the toe undermines it.
4. Keep deep-rooted native vegetation on slopes where practical. Roots help hold soil, but avoid over-watering landscaping on a hillside.
5. Maintain retaining walls and drainage structures, and have them inspected if you see bowing, tilting, or water ponding behind them.
6. Get a professional evaluation from a licensed geotechnical engineer or engineering geologist if you see signs of movement. Early stabilization is usually far cheaper than repair.
7. Plan for access loss. Keep an alternate route in mind and consider what you would need if your driveway washed out.
8. Sign up for alerts and make a plan. Enroll in VT-Alert and review Ready.gov guidance on landslides and debris flow, including what to do if you hear rumbling or see a slope start to move — move away from the path, not toward it.

Frequently asked questions

Does Vermont really have landslides?

Yes. Vermont's steep terrain, glacially deposited soils, and marine clay along the Champlain Valley make slope failures a recurring hazard. Most are small, shallow slides and rockfalls that affect roads and stream banks, but large events — including many during Tropical Storm Irene in 2011 — have damaged homes and infrastructure. Vermont Emergency Management tracks these hazards and coordinates response and recovery across the state.

Does homeowners insurance cover landslide damage in Vermont?

Usually not. Standard homeowners policies generally exclude earth movement, including landslide, slope failure, and sinkhole collapse. National Flood Insurance Program policies cover mudflow, which is a river of liquid and flowing mud, but they do not cover landslide. Ask a licensed Vermont insurance agent whether any endorsement or specialty policy is available for your property, and keep good records of your home's condition.

What are the warning signs that a slope near my home might fail?

Watch for new cracks in foundations, walls, or driveways; doors and windows that suddenly stick; tilting trees, fences, or utility poles; bulging ground at the base of a slope; and new springs or soggy areas after rain. Small rockfalls or muddy water in a nearby stream can also signal movement upslope. If you see these signs, contact a licensed geotechnical professional and consider limiting time in the most exposed part of the property, especially during heavy rain.

Official resources

• Vermont Emergency Management — state hazard information, alerts, and emergency preparedness guidance.
• USGS Landslide Hazards Program — science, monitoring, and landslide preparedness information.
• Ready.gov – Landslides and Debris Flow — what to do before, during, and after a landslide.