Scale & Key
Evidence codes
| Code | Evidence |
|---|---|
| -R | Radar measurement |
| -I | In-situ instrument |
| -P | Photogrammetry or video analysis |
| -E | Engineering or forensic reconstruction |
| -D | Damage-derived estimate |
| -T | Theoretical or retrospective reconstruction |
| -M | Multiple independent methods |
| + | High-confidence evidence |
| ? | Provisional or unusually uncertain |
Secondary profile
| Code | Meaning | Levels |
|---|---|---|
| I | Fatalities | I0 0 | I1 1-5 | I2 6-20 | I3 21-50 | I4 51-100 | I5 101+ |
| S | Maximum width | S0 <100 yd | S1 100-499 | S2 500-999 | S3 1-1.49 mi | S4 1.5-1.99 mi | S5 2+ mi |
| L | Track length | L0 <1 mi | L1 1-9 | L2 10-24 | L3 25-49 | L4 50-99 | L5 100+ mi |
Confidence assessment
The calculator gives a separate evidence-confidence score. It considers the method, measurement height, averaging period, uncertainty range, number of independent methods and whether the entered value is measured or reconstructed. It does not secretly add or subtract mph from the tornado.
TORRO T-scale comparison
| T | mph | T | mph |
|---|---|---|---|
| T0 | 39-54 | T6 | 161-186 |
| T1 | 55-72 | T7 | 187-212 |
| T2 | 73-92 | T8 | 213-240 |
| T3 | 93-114 | T9 | 241-269 |
| T4 | 115-136 | T10 | 270-299 |
| T5 | 137-160 | T11 | about 300-330 |
International Fujita comparison
The IF scale is not just a set of wind bins. Its formal method can use damage indicators and measured winds, and its wind definition differs from a standard three-second 10 m gust. The calculator therefore labels its output IF wind comparison, not an official IF rating.
Example: RWS6-R+ / I1 / S3 / L1 = RWS6 wind intensity, radar evidence, high confidence, 1-5 fatalities, 1-1.49 mile maximum width and a 1-9 mile track.