Heavy rainfall can do more than flood streets or leak through roofs. In some cases, it can cause the ground itself to move. When soils become saturated and lose stability, slopes may fail, sending soil, rock, and debris downhill in what is known as a landslide.

For property owners in hillside areas or anywhere with significant drainage or grading, landslides are a serious concern. They can damage structures, disrupt drainage systems, and create long-term stability issues if the underlying cause is not addressed.

Understanding how landslides occur, the conditions that trigger them, and what to do if one affects your property can help reduce risk and guide effective recovery.

What Is a Landslide?

A landslide is a type of ground failure caused by slope instability, where soil, rock, or debris moves downslope due to gravity. Landslides can occur suddenly during storms or develop gradually as soils weaken over time.

Landslides come in several forms depending on how material moves:

• Debris flows or mudflows – mixtures of soil, water, and debris that move rapidly downhill
• Soil slumps – sections of ground that rotate or drop along a curved failure surface
• Earth flows – slower movement of saturated soil
• Slope failures – collapse of soil or rock along a weakened plane

These events are often triggered by changes in water conditions within the soil. As water fills the spaces between soil particles, groundwater pressure increases and the friction that normally holds the slope in place decreases. When the resisting strength of the soil becomes lower than the pressures acting on it, the slope can fail.

Conditions That Cause Landslides

Landslides result from one or more factors that gradually weaken soil stability.

Heavy or Prolonged Rainfall

Rain is the most common cause of landslides. When soil becomes saturated:

• Groundwater pressure increases
• Soil strength decreases
• Slopes become less stable

This combination can cause soil layers to slide or collapse, especially on steep terrain. Intense storms can also produce large volumes of runoff from surrounding hillsides. In one investigated case, heavy rainfall overwhelmed natural drainage paths and carried thousands of cubic feet of mud and debris onto a residential property.

Poor Drainage

Blocked or poorly designed drainage systems can allow water to accumulate in soils. Culverts, drainage basins, and stormwater systems that become clogged with debris can concentrate water in areas not designed for prolonged saturation. Over time, this added moisture can weaken slopes and increase the likelihood of ground movement.

Wildfire Damage

In wildfire-prone regions like California, landslide risk often increases after fires. Wildfires destroy vegetation that stabilizes slopes, damage underground utilities, and leave soils more vulnerable to erosion. Rainfall on burned hillsides frequently produces mudflows and debris flows that move rapidly downhill.

Changes to Hillsides

Human activity can also contribute to landslides. Examples include:

• Poorly compacted fill soil
• Improper fill material and grading
• Construction debris on slopes
• Construction activity and vibrations
• Altered drainage patterns

Ruptured water lines releasing water underground Loose materials on slopes can easily be mobilized during heavy rain.

Seismic Activity

Earthquakes can weaken slopes or trigger landslides directly by shaking loose soil layers. Earthquakes can also cause land movement in flat areas in the form of lateral spread or liquefaction.

Why Landslides Matter for Buildings and Property

Landslides can affect far more than the ground. Because buildings, infrastructure, and utilities depend on stable soil, its movement can cause widespread damage.

Damage to Buildings

When soil beneath or around a building moves, foundations can shift or settle unevenly. This may result in:

• Cracking in foundations and walls
• Sloping floors
• Misaligned structural frames
• Misaligned door and window frames
• Separation of building components

Damage to Site Improvements

Landslides frequently damage nonbuilding structures and site improvements such as:

• Retaining walls and fences
• Driveways and walkways
• Landscaping

Investigations following ground failures often find erosion, sinkholes, and undermined structural elements that increase vulnerability to future storms.

Damage to Utilities

Ground movement can disrupt buried infrastructure including:

• Stormwater drainage systems
• Water supply lines
• Sewer or septic systems
• Irrigation systems

Once these systems are compromised, additional soil movement can occur, and flooding and erosion can worsen during future storms.

Warning Signs of a Landslide

Some landslides occur suddenly, while others develop gradually and show early warning signs.

Common warning signs include:

• New cracks forming in soil, pavement, or retaining walls
• Leaning fences, trees, or walls
• Slumping or bulging ground surfaces
• Areas of unusual erosion
• Mud or debris deposits after storms
• Sudden changes in drainage patterns
• Sinkholes or ground depressions

These signs may indicate that soils are shifting or that water is running and accumulating beneath the surface.

Understanding the Ground Beneath Your Property

Rainstorms and other sources of water can place significant stress on both buildings and the soils that support them. As slopes become saturated, changes in groundwater pressure can quickly alter the stability of the ground, sometimes resulting in landslides that affect structures, drainage systems, and surrounding infrastructure.

Recognizing the warning signs and understanding how these events occur can help property owners respond quickly and make informed decisions about repairs and site stability. Investigating conditions early often makes it easier to identify the root cause of ground and structure movement and reduce the risk of further damage.

Following a landslide, a forensic engineer can help property owners understand what caused the ground movement and how it affected structures, drainage systems, and surrounding site conditions. Through field observations, measurements, and engineering analysis, forensic engineers document the extent of damage and identify factors that contributed to the failure. This process helps guide repair planning and can provide valuable documentation for insurance, legal, or property management needs.

Transportation shapes access to nearly every part of daily life, from work to food, to essential travel.

Behind every route, stop, and schedule is a system that most riders never think about until something goes wrong. When that network is overlooked, the effects reach beyond those who rely on it. Not only are riders inconvenienced, but the vehicles themselves face heavier maintenance demands, shorter service life, and a greater operational strain.

For mass transit providers expanding service, the challenge isn’t just adding routes; it’s supporting the vehicles that make that service possible.

Planning additional transit services should consider all restrictions, including vehicle maintenance capacity.

While these transportation facilities should be close to service areas, they are the hardest pieces of infrastructure to site and approve.

Transit planning often separates what riders see from what keeps the system running. Routes and frequency lead the conversation. Bus depots, storage yards, and maintenance garages do not.

Guidance from the Federal Transit Administration mandates that transit service planning must coincide with capital infrastructure, including fleet storage and maintenance capacity. Buses require space for overnight storage, inspections, preventative maintenance and repair.

The ratio of vehicles per maintenance bay depends on service hours and miles and other factors, but in most cases, at least one bay for every 15 vehicles is recommended. Facilities also need sufficient room for storage of parts, fluids, tires, and other supplies. Areas for employee training, rest breaks and parking must be included.

Without this capacity, service cannot expand reliably.

Industry reports from the American Public Transportation Association point to growing pressure on transit operators to expand service while managing aging infrastructure and increasing fleet demands.

At the same time, building or expanding a bus maintenance garage introduces a different set of challenges. These sites require large parcels of land near service areas, access for large vehicle movement, and space for circulation, fueling, or charging. In dense communities, that kind of space is limited.

Even when the site is identified, approvals are not guaranteed.

Environmental review requirements under the National Environmental Policy Act require agencies to evaluate impacts such as traffic, noise, and air quality, and to engage the public in the decision-making process. This can often extend project timelines significantly, especially in developed areas where community concerns are high.

Service plans can move forward in months, while a new or expanded bus depot can take years.

In addition, the shift to electric fleets raises the stakes.

At Walker Consultants, our team has worked closely with the Fresno County Rural Transit Agency (FCRTA), to support the areas within the County lacking reliable transit access. We performed various studies and plans focusing on the implementation of fleet electrification and multimodal community resiliency hubs.

These studies evaluated what it would take for local energy grids to support a transition to zero-emission transit fleets, while exploring opportunities to capture and store energy, offset charging costs, and reduce long-term dependence on the electrical grid.

As part of that effort, resiliency hubs were designed to store and deliver backup power during emergencies, helping communities maintain access to vital services such as communication, heating and cooling, device charging, emergency coordination, and essential medical support.

Beyond cost and sustainability, these plans examined how transit systems would perform under real-world operating demands. For smaller, underserved communities across Fresno County, that means access to more reliable, cost-conscious transportation options built for long-term service.

When introducing EV transit services, maintenance areas are essential to sustaining a functionally balanced system.

Research from the National Renewable Energy Laboratory shows that electric bus depots frequently require additional space for charging infrastructure, changes to site layout and clearances, and substantial power upgrades. Existing diesel bus garages regularly need significant modifications to support these systems.

This limits where transit operators can expand and increases pressure to find new sites near existing routes.

The result is a disconnect.

A transit operator can approve more services, purchase additional buses, and secure funding, but without a nearby bus depot or maintenance garage with sufficient capacity, transit services will not match its potential.

Buses travel farther before starting service.
They cost more to operate.
They can break down more often, resulting in unreliable service.

Overcoming maintenance constraints

Transit expansion doesn’t stall because of lack of demand. It stalls when support systems are not planned at the same time.

Guidance from the Federal Transit Administration supports coordinated planning across service, fleet, and infrastructure.

Transit operators that avoid delays don’t just plan new routes. They ask:

• Where will these buses be stored?
• Which maintenance garage supports them?
• Do we need to expand the existing depot or build a new one?

This alignment prevents last-minute constraints.

New sites are difficult to approve, so many operators start with what they already own.

Common approaches:

• Reconfiguring existing bus yards to increase capacity
• Expanding maintenance garages where zoning allows
• Using temporary or satellite storage lots for overflow fleets

The American Public Transportation Association highlights how agencies extend the life and capacity of existing assets before pursuing new construction.

Bus depots are generally resisted at the neighborhood level.

Under the National Environmental Policy Act, projects must evaluate and disclose impacts, but early and consistent community engagement can reduce delays and improve project outcomes.

Planning for additional service means planning for where those buses live, not just where they run.

For help planning your next transit project, visit www.walkerconsultants.com.

As hurricane season approaches, building owners face the annual challenge of protecting their properties—and the people who rely on them.

From high-rise condos to public infrastructure, every structure has unique vulnerabilities, and now is the time to act.

At Walker Consultants, we’ve worked on both sides of the storm—helping clients fortify buildings in advance and investigating damage after the fact.

Our forensics and restoration experts have seen firsthand what works, what fails, and how preparation can make all the difference.

Assess Your Building Systems

Your building’s first line of defense against hurricane damage is its envelope—walls, windows, doors, and roof systems.

Even small breaches can lead to major water intrusion, organic growth, and costly downtime.

• Schedule a building envelope inspection. Look for signs of deterioration, improper seals, or required maintenance.
• Verify that vulnerable glazing systems can be protected from wind-borne debris impact, especially in older buildings.
• Inspect the roof for signs of uplift vulnerability, membrane damage, and flashing issues.
• For vertical transportation systems, review that controller rooms, machine rooms, and electrical spaces are protected from water intrusion where possible. Confirm sump pumps, drainage systems, and waterproofing protections serving elevator pits and lower-level equipment spaces are functional.

Understand the Risks of Wind and Water

Hurricane-force winds can exploit weaknesses in facades, drive rain sideways and dislodge unsecured equipment.

Water, both from rainfall and storm surge, is equally destructive.

• Assess flood vulnerabilities based on location and elevation. Consider flood-resistant upgrades for critical areas.
• Review elevator pits, machine rooms, and escalator equipment areas for flood exposure. Water intrusion in these spaces can damage critical components and lead to extended outages.

Review Your Emergency Response Plan

Preparedness isn’t just physical—it’s operational.

• Have an emergency response contractor on standby for post-storm damage assessment and water mitigation.
• Document your building condition before the storm with photos and notes. This supports faster insurance claims and repair planning.
• Ensure your tenants or occupants understand emergency protocols. Communication saves lives—and property.
• Coordinate in advance with your elevator maintenance provider and vertical transportation consultant on shutdown procedures, emergency power priorities, and post-storm response roles.

Plan for Recovery—Before the Storm

After a hurricane, building owners often scramble to assess damage, manage tenant expectations, and line up repair contractors.

• Work with a consultant now to create a post-event investigation and recovery strategy.
• Understand the typical failures for your building type so you can prioritize inspections and repairs efficiently.
• Invest in materials and details that reduce long-term vulnerability. Often, the most durable upgrades are the least visible.

Ready to Strengthen Your Building?

Walker Consultants offers proactive evaluations, building envelope and vertical transportation assessments, and post-storm forensic investigation and restoration services to help building owners weather the season with confidence.

Whether you’re preparing for the next storm or recovering from the last one, we’re here to help you build smarter—and rebuild stronger.