National Weather Service United States Department of Commerce

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!