Azimuth Stormglass™ Storm Report

Most storm reports answer one question: was there hail or wind near this address on this date? Stormglass answers it, then carries it to this roof: its height, the slopes that faced the storm, and where the wind pulls hardest. Every figure is public and carries its source, time and distance.

What sets it apart

• The wind at the roof, not at the airport. Airports measure at 33 ft over open ground. Stormglass carries the gust to this roof’s own height and ground cover with the ASCE 7-16 gust profile, plus the speed-up of a hill read from the USGS ground along the wind.Check it: ASCE 7-16 §26.7–26.8 and Table 26.11-1; USGS 3D Elevation Program.
• The roof itself, measured. Every roof plane’s pitch, facing and height, drawn on the aerial, with the slopes that faced the wind marked and the ASCE 7 edge, corner and ridge zones shaded.Check it: Google Solar API; ASCE 7-16 Chapter 30.
• How tall the storm stood, not only how strong. From the raw radar over the property: how high the 45 dBZ echo reached above the freezing level the weather balloon measured — the published hail test — with the Weather Service’s dual-polarization hail class and hail differential reflectivity.Check it: NOAA NEXRAD Level II and III; NOAA upper-air soundings; Waldvogel, Federer & Grimm (1979).
• Hail at the property and around it. NOAA’s multi-radar hail estimate at the property’s own square and within 1, 3, 5 and 10 miles; radar hail signatures; ground reports; warnings with their tags.Check it: NOAA MRMS; NOAA NCEI Severe Weather Data Inventory; NWS storm reports and warnings.
• Hail energy at each roof slope. The angle the hail struck each slope and the joules it drove in, from the hail size, the wind and the plane’s own pitch and facing — with its limits printed.Check it: the formulas in Section 5 of the science page; Heymsfield et al. (2018).
• The wind three ways. Airport stations, the Doppler radar’s wind over the property, and NOAA’s hourly surface analysis on a 1.6-mile grid — each labelled for what it is.Check it: NWS ASOS; NEXRAD velocity; NOAA URMA.
• Nothing hidden. No proprietary score. The method and its limits are printed; every line can be pulled again from NOAA, USGS and Google.Check it: the Sources table on the last page of every report.

How the roof is measured

Google’s roof model gives each plane’s pitch, facing, area and height above sea level; Stormglass subtracts the USGS bare-earth ground height to get the mean roof height ASCE 7 uses. Without it: OpenStreetMap, the story count or a photograph, named on the report.

How it is done

What’s in the report

1. Summary — hail at the property, the closest gust, the wind at this roof, the strongest echo
2. The storm aloft — how strong and how tall
3. The wind as measured — stations, reports, warnings
4. The wind from the radar and the surface analysis
5. The wind at this roof — exposure, height and hill
6. How wind loads a roof — zones 1, 2 and 3
7. This roof — aerial, planes, the slopes that faced the wind
8. Hail at and around the property
9. Hail energy at each slope — joules, by plane
10. Damage photographs by zone, when the inspection adds them
11. Notes, method and sources

How the wind is carried to the roof

Wind is slowed by the ground, so it blows harder higher up, and harder still over open water than over a town. ASCE 7-16, the standard the building codes adopt, gives the profile:

z is the roof’s mean height; α and b̂ come from the exposure — the ground the wind crossed (B: town and trees; C: open country, as at an airport; D: open water and flats). The hill speed-up follows ASCE 7-16 §26.8 from the ground profile along the wind.

A 70 mph gust at the airport becomes…	Exposure B	Exposure C	Exposure D
a 35 ft roof	59 mph	70 mph	75 mph
a 120 ft roof	71 mph	80 mph	84 mph
on the brow of a hill	often another 5 to 20 percent, from the ground profile

The plain power law alone ranks these backwards (the 120 ft roof at 84 mph in town, 78 on open water); the ASCE profile carries the ground’s friction. The report shows both.

Where the wind pulls hardest

Uplift is strongest at the corners (zone 3), then the eaves, rakes, ridge and hips (zone 2), least in the field (zone 1). Damage gathered in zones 2 and 3, on the slopes that faced the wind, is the pattern a wind loss leaves.

The record and the roof. The record shows whether a qualifying storm reached the property, and how hard; the roof shows whether it did the damage. Stormglass sits beside the inspection, never in place of it.