Here are some numbers for those of you who are interested in the how much
"punch" a hailstone has. Values here are for freefall only. You'd have to
increase/decrease it for wind effects. This was posted by Tim Marshall on the U.S.
chase listserver.
| Hail Size (IN) |
Freefall Velocity (MPH) |
Freefall Energy (FT-LBS) |
|
|
|
| 1/2 |
34.7 |
.009 |
| 3/4 |
42.3 |
.044 |
| 1 |
49.8 |
1.43 |
| 1.25 |
55.9 |
3.53 |
| 1.50 |
61.4 |
7.35 |
| 1.75 |
66.2 |
13.56 |
| 2 |
71.6 |
23.71 |
Thus, a 1.25 inch hailstone has about 2.5x the punch of a one inch hailstone and a 2 inch
hailstone has about 17x the punch of a one inch hailstone. OUCH! The rapid increase in
freefall energy causes a sharp damage threshold for most roofing and siding products as
well as vehicle metal. This occurs in the 1 to 1.5 inch diameter range. Keep in mind that
hail will fall at different velocities due to its shape, density, spin axis, collisions
with other stones, etc. Small hail tends to "float" due
to air resistance.