Hail Hits the Windward Slope First, So Start the Walk There

After a hailstorm in St. Louis, many homeowners walk the yard, look at the gutters, and then wonder which part of the roof to check first. Hail does not fall straight down in most storms. Wind leans the stones, and the slope facing into that wind takes the impacts at a steeper angle. Knowing which slope that is before anyone climbs gives you a starting point for the photos and a way to read the rest of the roof.

Why the windward side takes the first hits

Hail in a convective storm is carried by wind that can blow hard from one direction for the length of the storm cell. The stones strike the slope facing the wind more directly, and the far side gets lighter, more scattered impacts. That is why a neighbor's roof across the street can show a different pattern from yours, even on the same afternoon.

Many of the storms that move through the metro travel from the west or southwest, but the direction changes from one storm to the next. Do not assume the slope you can see from the street is the one that took the damage. If you can get the weather record for the day, note which way the wind was blowing when the hail fell. Your roofer or inspector can use the same information when they plan the walk.

What the windward slope usually shows

Start with the slope that faced the wind, then move to the others. On asphalt shingles, hail leaves granule loss, bruises that feel soft when pressed, and in severe cases cracks in the mat under the granules. Granule loss often shows as bare dark spots on the shingle or as granules collected in the gutter below. A bruise is the soft spot you can feel with a finger. Mark the location of each area on a simple sketch of the roof, and keep the sketch with the photos.

The leeward slope may show fewer marks, and a count of zero on that side does not mean the roof is clear. Hail can strike from more than one direction in a single storm, especially when the wind shifts during the cell. Walk every slope, including the small ones over porches and dormers, and record what you see on each one.

Why bruises matter after the freeze

A bruise on an asphalt shingle may not leak at first. The mat under the granules is weakened, and the first winter brings freeze and thaw cycles that can open small cracks. St. Louis winters swing above and below freezing many times between November and March. Water that gets into a bruised spot can freeze and widen the damage. That is why the windward photos matter even when the roof looks fine from the driveway. The file you make now becomes the comparison point if the same slope shows a problem later.

Your neighbor's roof is not a substitute for your own walk. Two houses on the same block can show different hail patterns because the roof pitch, the tree cover, and the orientation of each slope change how the stones land. Use a neighbor's roof only as a reminder to look, not as evidence of what happened on yours.

Photograph the windward side at a fixed distance

Photographs taken from the ground are hard to use later unless they are consistent. Stand back at the same distance for each slope, shoot straight on, and include a reference object such as a tape measure or a coin placed on a shingle. Then take a close photo of any area that looks bruised, with the same reference in view. Date stamps on the phone help, but the more useful record is the position of each photo on your sketch.

Keep the sequence consistent. Shoot the front slope from left to right, then the next slope in the same order. Anyone reading the file can then match the photos to the sketch without asking where each one was taken.

Ridge, eave and the metal on the same side of the house

Ridge caps and the top courses at the eave take hail and wind together. On the windward side, the ridge cap is struck more directly, and the first course at the eave can show lifted or bruised granules. Check the ridge from a ladder placed on the leeward side, and do not lean across the peak to reach it.

Ice damming shows up at the eave too, but that is a winter problem with a different cause. Do not confuse a winter edge stain with a hail mark. Hail leaves a scatter of small round impacts across the surface, while ice-related damage follows the eave line and often traces toward the warm spots in the attic.

Look at the metal on the same side of the house as the windward slope. Gutters, downspouts, the drip edge, the vent hood at the ridge, and the outer cover of an air conditioner all take hail impacts. Dents on the metal that faces the storm agree with what you find on the roof. Dents only on the back of the house, with a clean front roof, are worth a second look before you draw any conclusion.

What to write down before the roofer arrives

• The date and time of the storm, and the wind direction you remember or can look up.
• A sketch of the roof with each slope labeled and the windward side marked.
• Photos of each slope taken from the same distance, with a reference object in frame.
• Close photos of each bruise, with the reference object in view.
• Notes on the metal on the same side of the house, including gutters and downspouts.

What the walk costs, and what the price should cover

A written inspection and a documented walk of each slope is a separate line from any repair. Ask whether the price covers a walk of every slope, the sketch, and the photo file, or only the slope facing the street. A quote that covers only the front may leave the windward side unchecked, and that is the side most likely to need the closest look. Ask for the scope in writing before anyone starts the work.

Keys documents damage, gives the homeowner a written scope with photos and measurements, and attends as the contractor while the homeowner deals with their own insurer. Keys does not handle or negotiate an insurance claim for a homeowner, because Missouri law (RSMo 407.725) bars a roofing contractor from representing or negotiating a homeowner's insurance claim.

What to ask

• Which slope did you walk first, and which one did you record as the windward side?
• Did you check every slope, including the small roofs over porches and dormers?
• Can I have the photo file and the sketch, not just a summary?
• What shingle type is on the roof now, and does the damage show the same way across every slope?

When to call

If you have marked the windward side and want someone to walk it with you, call the Keys office at (314) 220-2333. Plan the walk for a dry day, when the shingles are not wet and each slope can be read clearly. Bring the sketch and the photo file, and the walk goes faster for everyone.