Tips for Estimating Wind Speeds for SWOP Observers

Beaufort Wind Estimation Scale

Beaufort #	MPH	Description	Specification
0	<1	Calm	Smoke rises vertically
1	1-3	Light Air	Direction of wind shown by smoke drift but not by wind vanes
2	4-7	Light Breeze	Wind felt on face; Leaves rustle; Wind vanes moved by wind
3	8-12	Gentle Breeze	Leaves and small twigs in constant motion; Wind extends light flag
4	13-18	Moderate	Raises dust, loose paper; Small branches moved
5	19-24	Fresh	Small trees begin to sway; Crested wavelets form on inland waters
6	25-31	Strong	Large branches in motion; Whistling heard in telephone wires; Umbrellas used with difficulty
7	32-38	Near Gale	Whole trees in motion; Inconvenience felt walking against the wind
8	39-46	Gale	Twigs break off trees; Wind generally impedes progress; Mobile homes may shake
9	47-54	Strong Gale	Slight structural damage occurs; Mobile homes, sheds, roofs, lanais, and RV's suffer minor damage
10	55-63	Storm	Small trees uprooted; Moderate damage occurs to mobile homes and RV's; Brick and wood frame houses receive minor structural and roof damage; Some signs blown down
11	64-73	Violent Storm	Moderate sized trees uprooted; Large branches snapped off trees; Chimneys and road signs toppled; Significant mobile home damage; Power lines downed
12	74-95	Hurricane	Mobile homes overturned; Large trees and branches downed; Moderate roof damage to wood and brick homes; Minor pier damage

Estimating wind speed is a difficult task, and the above scale is meant simply as a guide. Within the SWOP program, we are much more interested in the damage incurred by the wind rather than an actual speed. If you have reliable wind equipment, you are welcome to send us actual values. If you don't have equipment or don't feel comfortable guessing the wind speed at your location, a description of the damage that occurred will certainly suffice. Instead of wind speed values, report any of the following:

1) Branches blown down in your yard (provide diameter if possible)

2) Trees snapped or knocked down

3) Shingles or siding damaged

4) Powerlines blown down

5) Other structural damage

NOTE: Always beware of second-hand reports! Only report what you actually see...or if you want to pass along a report from another source, please let us know!