The TORRO hail storm intensity scale extends from H0 to H10, with increments of intensity or damage potential related to the following criteria:
- Hail size (distribution and maximum)
- Texture
- Numbers
- Fall speed
- Speed of storm translation
- Strength of accompanying wind.
Characteristic damage associated with each increment is listed in the table below but can be modified to reflect differences in building materials and types (for example, if roofing tiles are predominantly slate, shingle, or concrete).
The following table describes the TORRO hail storm intensity scale and damage associated with each degree of severity.
| TORRO Hail Storm Intensity Scale | ||||
| Scale | Intensity Category | Typical Hail Diameter (mm)* | Probable Kinetic Energy (J/m2) | Typical Damage |
| H0 | Hard hail | 5 | 0-25 | No damage. |
| H1 | Potentially damaging | 5-15 | >25 | Slight damage to plants, crops. |
| H2 | Potentially damaging | 10-20 | >125 | Significant damage to fruit, crops, vegetation. |
| H3 | Severe | 20-30 | >275 | Severe damage to fruit and crops; damage to glass and plastic structures; paint and wood scored. |
| H4 | Severe | 25-40 | >450 | Widespread glass damage; vehicle bodywork damage. |
| H5 | Destructive | 30-50 | >650 | Wholesale destruction of glass; damage to tiled roofs; significant risk of injuries. |
| H6 | Destructive | 40-60 | - | Aircraft bodywork dented; brick walls pitted. |
| H7 | Very destructive | 50-75 | - | Severe roof damage; risk of serious injuries. |
| H8 | Very destructive | 60-90 | - | Severe damage to aircraft bodywork. (Severest recorded in the British Isles). |
| H9 | Super hailstorm | 75-100 | - | Extensive structural damage. Risk of severe or even fatal injuries to persons caught in the open. |
| H10 | Super hailstorm | >100 | - | Extensive structural damage. Risk of severe or even fatal injuries to persons caught in the open. |
| * Approximate range, since other factors (number and density of hailstones, hail fall speed, and surface wind speeds) affect severity. | ||||