Measured reports are preferred over
estimated reports, as they are generally more accurate. However,
sometimes it's hard to estimate properly under severe weather
conditions. Over-estimating is as bad or worse than under-estimating
storm conditions.
Here are guidelines for
estimating in your reports.
Hail
Size
Pea Size
1/4"
Dime Size 1/2" (Minimum
reportable size)
Penny Size
3/4"
Nickel Size 1"
Golf Ball Size
1-3/4"
Baseball Size 2-3/4"
Snow Intensity
Light
Visibility > 1/2 mile.
Moderate Visibility > 1/4 mile
but <= 1/2 mile.
Heavy
Visibility <= 1/4 mile.
Rain
Intensity
Light
Less than 0.2"/Hr.
Moderate 0.2" to
1.0"/Hr.
Heavy
1.1" to 2.2"/Hr. (Minimum reportable rain)
Very heavy
2.3" to
4.5"/Hr.
Intense 4.6"
to 7.1"/Hr.
Extreme More than
7.1"/Hr.
Wind Speed (Miles Per Hour)
0 (Calm) Smoke
rises vertically
1-3 Smoke drifts but windvanes do not
move
4-7 Wind felt on face, leaves rustle
8-12 Small twigs in
motion
13-18 Dust raised, loose paper raised, small branches
move
19-24 Small leafy trees move, crested wavelets form on
water
25-31 Large branches in motion, whistling in wires
32-38 Whole trees in motion, inconvenience felt walking against
wind
39-54 Twigs break off trees
55-72 Damage to chimneys,
pushes over shallow rooted trees
72-112 Peels surface off roofs,
windows broken, trailer homes overturned
113-157 Roofs torn off
houses, trailers destroyed, large trees snapped and uprooted
158
+ Severe damage, cars lifted off ground (life passes before
your eyes)
Beaufort Wind
Scale
|
Beaufort
Number |
Wind Speed
(MPH) |
Description |
|
0 |
<1 |
Calm; smoke rises vertically. |
|
1 |
1-3 |
Direction of wind shown by smoke drift; wind vanes
unaffected. |
|
2 |
4-7 |
Wind felt on face; leaves rustle; wind vanes
move. |
|
3 |
8-12 |
Leaves and small twigs in constant motion; wind will
extend a flag. |
|
4 |
13-18 |
Raises dust, loose paper; small branches move.
|
|
5 |
19-24 |
Small trees with leaves begin to sway; crested waves
form on inland waters. |
|
6 |
25-31 |
Large branches in motion; whistling heard on telephone
wires; umbrellas difficult to control. |
|
7 |
32-38 |
Whole trees sway; walking into wind becomes difficult.
|
|
8 |
39-46 |
Twigs break off trees; cars veer on
roads. |
|
9 |
47-54 |
Slight structural damage occurs (roof shingles may blow
away, etc.) |
|
10 |
55-63 |
Large trees uprooted; considerable structural damage.
|
|
11 |
64-72 |
Widespread damage. |
|
12 |
73 + |
Hurricane force; widespread
damage. |
|
