A term of the record

EF rating

Enhanced Fujita scale rating. A tornado's strength as a survey team rated it from the damage it left, on a scale whose wind speeds are inferred from that damage and not measured.

Definition

Related pages: 4
Last revised: 23 August 2026

An EF rating is the category a survey team assigns to a tornado after walking its path, from EF0 at the low end upward to EF5. The Enhanced Fujita scale replaced the original Fujita scale so that the rating would rest on a defined method: the team identifies each damage indicator along the path, a kind of structure or tree, notes the degree of damage it suffered, and reads from a table the wind speed that degree of damage to that kind of thing implies. The highest such speed along the path sets the rating.

The wind speeds on the scale are therefore estimates, derived from what broke, and the scale says so. Few anemometers stand in a tornado's path, so the rating is the best available statement of its strength, made by trained people afterward from the evidence on the ground. Two consequences follow for a claim. A rating describes the strongest point of the path, not every point on it, so a property inside the footprint of a strong tornado may have seen far less. And a rating depends on what stood in the way: a tornado over open fields leaves less to rate and may be rated lower than its wind deserved.

The product prints a rating as the survey published it, and the wind speed beside any surveyed structure as an estimate labelled in type, because it is the scale's implied wind for that damage. A rating is an observation of damage, not a measurement of wind, and the document does not promote it into one.

In the report

How the document prints it

In the report a rating appears in the damage survey section beside the path's name and date, with the path's length and width where the survey published them and a sentence saying whether the address lay inside the surveyed footprint. Beneath it, the structures the survey team examined nearest the address are listed with what each was, what the survey found, and the rating that damage implies, every wind beside them marked as estimated. In the record table a tornado row prints the rating as its measurement, with its source and citation, and a survey not yet quality controlled is labelled so.

The terms this page uses and the guides that go further. Each is shown against its own example from the record.

Term Storm survey
A ground or aerial examination of storm damage by a National Weather Service team, made to fix a tornado's path, width and rating after the event.
Term Storm path
The track a storm or tornado followed across the ground, recorded as a surveyed line, a pair of endpoints or a sequence of reports.
Term Peak gust
The highest wind speed recorded over a brief interval, a few seconds, at a station or by an observer during a storm or a day.
Guide NOAA's Storm Events database, explained
The Storm Events database is the reviewed record of severe weather in the United States, kept by the National Centers for Environmental Information from the entries each forecast office prepares under a written directive. This guide states what is in it, how a hail entry is made, why it arrives a season after the storm and can change after that, what it does not hold, and how to read it beside the preliminary log and the local storm report an entry began as.

Sources

The primary references. Each opens on the agency's own site.

The next step

The glossary defines the word. The report is what uses it.

Everything above is definition: what the word means in the document, and what it does not. None of it says what reached one roof.

Run the address and the archive is searched at the property: the storm, the date, the measured size, the distance and bearing from the roof, and the federal record each figure came from, in a document that states its own method. About a minute.

Suggestions by Google

First reports free
No card required
Ready in a minute

How this page is made

The text: Written by the editors and last revised 23 August 2026. It explains the record and how the report reads it; it contains no figure of its own.
The example: The archive holds nothing this page could show yet, so no example is printed. One appears, computed rather than written, as soon as the record holds a relevant day.
Measured and detected: A report from a person or an instrument is measured. A radar-derived size is detected, not measured, and is marked as such, here and in every document we issue. The two are never added together.
What this is not: A definition of a word the report uses. It is not a report on any property, and it states no opinion about one. The coverage page states what the record holds, by kind and by year.

About this record

Everything here is reproduced from public federal and volunteer weather records, as the agencies and observer networks that publish them released it. Titan Weather compiles the record; it does not observe the weather, and it is not affiliated with any source it cites.

No archive holds everything. Storms cross places where nobody is standing, instruments and spotters cover some areas better than others, sources revise their records, and recent reports can take weeks to arrive and settle. Where this page shows nothing, nothing was found in the sources searched, within the period and area it states. That is not a finding that no weather occurred.

These pages describe the public record near a place or on a date. They do not establish what reached any particular property, and nothing here is insurance, legal or engineering advice.