StormProof → guides → What counts as "severe" hail — and why 1 inch is the line

What counts as "severe" hail — and why 1 inch is the line

The National Weather Service classifies a thunderstorm as severe when it produces hail of 1 inch in diameter or larger (quarter size), wind gusts of 58 mph or more, or a tornado. The hail criterion was raised from 3/4 inch to 1 inch nationally in 2010, aligning warnings with the size at which property damage becomes common.

For claim work, the criterion is a vocabulary, not a damage threshold: asphalt shingles can be bruised by smaller stones under the right wind, and slate or metal can shrug off larger ones. But "≥1-inch reports near the address" is the standard, checkable measure of whether a damaging-class storm passed — which is why our season pages and reports count against that line and state the actual recorded sizes.

What hail size damages an asphalt shingle roof?

Industry testing and insurer practice generally treat 1 inch as the size where asphalt-shingle damage becomes plausible and 1.25–1.5 inches where it becomes common; wind, shingle age and brittleness move the line in either direction. The recorded size near the address is the anchor fact; the roof inspection determines what it did.

How is hail size reported — who measures it?

Trained spotters, the public, emergency managers and NWS staff report sizes, usually by comparison to coins and balls (quarter = 1", golf ball = 1.75", baseball = 2.75"). Offices quality-control the reports into Storm Events. Sizes are observations at points, not maxima for the whole storm footprint.

Is hail under 1 inch ever claim-relevant?

Yes — sub-severe hail with strong wind can mark soft metals and aged shingles. It is simply less common and harder to attribute. The record still helps: it documents what sizes were actually observed nearby, in either direction.

Sources and standing caveat

Official records referenced throughout: NCEI Storm Events Database (the official NWS storm record, 1950–present) and SPC daily storm reports (preliminary, same-day). NWS records are point and path observations. The absence of a nearby report does NOT prove that no hail fell at this address — it means no observation was logged nearby. A report of nearby hail documents the event; it does not by itself prove damage to a specific structure. Nothing on this page is legal, insurance, or public-adjusting advice — deadlines, coverage and remedies are policy- and state-specific.

Put the record in the file

A per-address verification report compiles every NWS-recorded hail and wind event within 1, 3 and 10 miles of any US address — distances, official narratives, citations, provenance labels — formatted as an insurance-appeal attachment, hosted on HailEvidence (the neutral evidence surface).

Unlimited reports — Pro $99/mo Single report $29