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What Types of Damage Does a Severe Thunderstorm Cause?

Last updated October 31, 2026

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The short answer

Direct Water Intrusion from Rain and Flooding

Wind-driven rain can push water through roof edges, window seals, and siding gaps. If your roof has existing damage, it may fail completely under heavy downpours. Flash flooding can overwhelm gutters and downspouts, sending water into ground-level spaces. Standing water then begins to soak into walls, insulation, and flooring, requiring immediate extraction.

Ground saturation can cause water to seep through foundation cracks or walls. This flooding can damage appliances, HVAC systems, and personal belongings. The longer water sits, the more it warps wood, swells drywall, and degrades materials. Clogged exterior drains during heavy rain can quickly lead to water entering your home.

Wind Damage to Roofs and Building Envelopes

High winds can lift shingles, tear off roof flashing, or dislodge entire sections of roofing material. Once the roof is compromised, your home is open to further water damage. Winds can also pry open windows and doors, allowing rain and debris to enter. Siding and exterior trim can be ripped away, exposing the wall structure.

Flying debris, like patio furniture or tree branches, can break windows and puncture siding. A broken window creates an immediate opening for more rain. The force of wind can also stress and weaken the structural connections in your attic and walls. This damage often requires professional assessment to ensure your home remains safe and sound.

Hail Impact and Lightning Strikes

Hailstones can severely damage roofing materials, reducing their lifespan and creating entry points for water. The impact can crack tiles, puncture soft metals, and granulate asphalt shingles. This damage is not always obvious from the ground, so a roof inspection after a storm is wise. Compromised shingles will leak during the next rain, leading to hidden water damage.

A direct lightning strike can cause a fire in your roof or attic. Even a nearby strike can send a massive power surge through your home's wiring. This surge can destroy televisions, computers, and kitchen appliances. The electrical system itself may be damaged, creating a fire hazard that requires an electrician to inspect.

  • Dented or cracked roof shingles and tiles
  • Shattered skylights, windows, and vinyl siding
  • Damaged gutters, downspouts, and outdoor HVAC units
  • Pitted or cracked stucco and exterior paint
  • Fire from lightning igniting attic framing or wiring
  • Power surges that damage electronics and appliances

Secondary Damage from Lingering Moisture

After the storm passes, hidden moisture becomes the primary threat. Water inside walls and under floors creates an ideal environment for mold, which can begin growing within a day or two. Mold damages building materials and can affect indoor air quality. Wet insulation loses its ability to insulate and may need complete replacement.

Wood framing and subfloors that stay damp will swell and warp. Over time, they can rot and weaken, compromising the structure's integrity. Metal fasteners and plumbing within walls can also corrode. Addressing these secondary issues requires thorough drying and often repair work by qualified professionals.

Steps to Take After a Storm

First, ensure it is safe to re-enter your home. Check for structural hazards, downed power lines, or gas leaks. If safe, document all visible damage with photos and videos for your records and your insurance company. Move undamaged belongings to a dry area and begin removing standing water if you can do so safely.

Contact your insurance company to start a claim. Then, call local water damage pros for a thorough inspection and assessment. They have the tools to find hidden moisture and can create a plan for drying and restoration. Policies vary, and your insurer decides what is covered. Taking action quickly helps prevent more extensive and costly repairs later.

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Phones are answered 24/7 for San Bernardino and nearby communities.

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Frequently asked questions

Does home insurance cover storm damage?

Most standard policies cover sudden, accidental damage from wind, hail, and lightning. However, damage from flooding typically requires separate flood insurance. Always review your specific policy details and report damage quickly. Policies vary, and your insurer decides what is covered.

How soon should I call for water damage help?

You should contact local water damage pros as soon as it is safe to do so. Mold can begin growing very quickly. A prompt inspection can identify hidden moisture and prevent secondary structural damage and mold growth from taking hold in your home. Acting quickly helps minimize the extent of repairs needed.

What if I only see a small leak after a storm?

A small visible leak often indicates a larger problem in your roof or walls. Water travels along framing and can pool far from the original entry point. Have a professional perform a water damage inspection to assess the full extent and prevent unseen rot or mold.

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