Solar Panels in Snow, Hail and Storms: What to Expect

Snow, hail, and storms are common concerns for solar panel owners. This page explains how these weather conditions affect both the performance and the physical integrity of photovoltaic (PV) systems. It separates normal behavior from actual faults, helping you understand what to expect and when to investigate further.

How Snow Affects Production

Snow affects solar panels in two main ways: by blocking light and by adding weight. Both are temporary and rarely cause damage.

Light Blockage

A layer of snow on the panel surface prevents sunlight from reaching the solar cells, so production drops to near zero. This is a normal and expected condition. The panel is not broken; it is simply shaded. Once the snow melts or slides off, production returns to normal.

Most panels are mounted at an angle, which encourages snow to slide off naturally. The smooth glass surface and the heat generated by the panel (even when producing a little) help melt the snow from the bottom up. This self-clearing effect is more pronounced on steeper roofs and in sunnier conditions.

Weight and Structural Load

Snow accumulates on panels just as it does on a roof. The weight can be significant, but panels are designed and tested to withstand typical snow loads. Building codes specify minimum snow load requirements for roofs, and solar panels are installed to meet those same standards. The racking and mounting system is engineered to handle the combined weight of panels and snow.

However, extreme snowfalls that exceed local building codes can stress the mounting system. If you live in an area with record snowfall, it is wise to have a professional inspect the roof and mounting structure, especially after a historic storm. But for ordinary winters, snow is not a structural concern.

Does Snow Damage Panels?

Snow itself does not damage the panels. The materials—glass, aluminum, and silicon—are chosen to withstand freezing temperatures and thermal cycling. The main risk is from ice dams or sliding snow, which can sometimes catch on the edge of a panel and cause mechanical stress, but this is rare and usually minor.

Should You Remove Snow from Panels?

In most cases, no. Panels are designed to shed snow on their own, and removing snow can be dangerous. Climbing onto a roof in winter conditions is risky, and using a shovel or rake can scratch the glass or damage the frame. If you must remove snow, use a soft brush with a long handle, and never use metal tools. But remember: the energy lost to snow is often less than the risk of injury or damage. In many regions, snow melts within a few days, and the annual production loss is small.

Hail and Impact Resistance

Hail is a common worry, but modern solar panels are built to withstand most hailstorms.

Testing and Ratings

Solar panels are tested for impact resistance using a standardized test. A steel ball (or in some standards, a simulated hailstone) is fired at the panel at a specified speed. Panels are rated by the size and speed of the projectile they survive. Most panels are rated for hail up to 1 inch (25 mm) in diameter at speeds up to 50 mph (80 km/h). This is sufficient for the vast majority of hailstorms.

What Happens When Hail Hits?

The glass front of a panel is tempered, similar to car windows. It can withstand a surprising amount of impact. When hail hits, the energy is spread across the surface, and the glass flexes slightly. If the impact exceeds the panel’s rating, the glass may crack, but the panel may still produce electricity if the cells are not damaged. However, cracks can allow moisture to enter, leading to corrosion and eventual failure.

Signs of Hail Damage

After a severe hailstorm, inspect the panels from the ground or with binoculars. Look for:

• Cracks in the glass (often visible as lines or spiderwebs)
• Chips or pits on the surface
• Discoloration or burn marks (indicating cell damage)
• Water spots or condensation inside the panel (a sign of seal failure)

If you see any of these, contact a professional for a closer inspection. Small cosmetic chips may not affect performance, but any crack that compromises the seal should be addressed.

Does Hail Damage Affect Performance?

Minor hail damage may not reduce output immediately. The cells are protected by the glass, and a few cracks in the glass may not block much light. However, over time, moisture can enter and cause corrosion, leading to a gradual decline in performance. It is best to have any damage assessed by a professional.

Storms and Wind

Storms bring wind, rain, and sometimes lightning. Each has its own effect on solar panels.

Wind Load

Solar panels are designed to withstand high winds, typically up to 140 mph (225 km/h) or more, depending on the mounting system. The racking is anchored to the roof with bolts and rails, and the panels are clamped to the rails. The system is engineered to resist uplift and lateral forces. In most storms, panels are unaffected.

However, if a panel is not properly installed or the mounting hardware is corroded, wind can cause damage. After a major storm, check for loose panels, bent racks, or debris that may have struck the array. If anything looks out of place, have it inspected.

Rain and Water

Rain is not a problem for solar panels. They are sealed against moisture, and the glass is designed to shed water. Rain actually helps clean the panels, washing away dust and pollen. The main concern is if water gets inside the panel or the electrical connections, which can happen if seals fail or connectors are not properly mated. But this is rare and usually a result of poor installation or damage.

Lightning

Lightning can strike panels or nearby structures, causing surges that can damage inverters or other electrical components. Most systems include surge protection, and grounding helps dissipate the energy. If a lightning strike occurs near your system, it is wise to have the system checked by a professional, even if it appears to be working. Surge damage may not be immediately apparent.

What People Get Wrong About Weather and Solar Panels

A common misconception is that a drop in production after a storm means the panels are damaged. In reality, the most likely cause is a temporary condition such as snow cover, debris, or grid outage. Panels are resilient, and most weather events do not cause lasting damage.

Another mistake is assuming that hail damage is obvious. Sometimes the damage is invisible to the naked eye, especially if the cells are micro-cracked. Micro-cracks can develop from thermal stress or hail impacts and may not affect performance initially, but they can grow over time, leading to power loss. This is why professional inspections are recommended after severe weather.

Finally, some people think that panels need to be cleaned after every snowstorm. As mentioned, this is unnecessary and risky. Panels are designed to shed snow, and the energy gain from cleaning is often minimal compared to the risk of injury.

Comparison: Normal vs. Faulty Behavior

What to Do After Severe Weather

1. Inspect from the ground: Look for obvious damage to panels, racking, and wiring.
2. Check production: Compare your system’s output to a sunny day. If it’s significantly lower, it may be due to debris or damage.
3. Contact a professional if you see damage or if production does not recover within a few days.

Remember, solar panels are designed to withstand the elements. Most weather events are not a cause for concern. When in doubt, a professional inspection can provide peace of mind.

FAQs

Do solar panels work in winter?

Yes, solar panels work in winter, but production is lower due to shorter days and lower sun angle. Snow can temporarily block light, but panels are designed to shed snow and will resume production once clear. Cold temperatures actually increase panel efficiency slightly.

Can hail damage solar panels?

Hail can damage solar panels if the hailstones are large enough and moving fast enough. Most panels are tested to withstand 1-inch hail at 50 mph. Larger hail can crack the glass, but the panel may still produce power. If you suspect hail damage, have it inspected.

Should I remove snow from my solar panels?

Generally, no. Panels are designed to shed snow on their own. Removing snow can be dangerous and may damage the panels. If you must remove snow, use a soft brush and never use metal tools. The energy loss from snow is usually small.

How much snow can solar panels hold?

Solar panels are designed to handle typical snow loads as specified by local building codes. The exact amount depends on the mounting system and roof. Extreme snowfalls can stress the system, so it’s wise to have it inspected after record storms.

What should I do after a storm?

Inspect your panels from the ground for visible damage, check your system’s production, and contact a professional if you see anything unusual. Most storms do not cause damage, but it’s good to be vigilant.