Lake effect snow will continue into the weekend as two more quick moving systems will bring widespread snow to the Upper Great Lakes. High winds are expected across portions of Montana through the weekend. Below normal temperatures will remain in place across much of the southern and eastern U.S., while the western U.S. will experience above normal temperatures. Read More >
Portland, OR
Weather Forecast Office
[ Also, see estimating wind speed and sea states while at sea ]
Beaufort number | Description | Speed | Visual Clues and Damage Effects |
---|---|---|---|
0 |
Calm | Calm | Calm wind. Smoke rises vertically with little if any drift. |
1 |
Light Air | 1 to 3 mph | Direction of wind shown by smoke drift, not by wind vanes. Little if any movement with flags. Wind barely moves tree leaves. |
2 |
Light Breeze | 4 to 7 mph | Wind felt on face. Leaves rustle and small twigs move. Ordinary wind vanes move. |
3 |
Gentle Breeze | 8 to 12 mph | Leaves and small twigs in constant motion. Wind blows up dry leaves from the ground. Flags are extended out. |
4 |
Moderate Breeze | 13 to 18 mph | Wind moves small branches. Wind raises dust and loose paper from the ground and drives them along. |
5 |
Fresh Breeze | 19 to 24 mph | Large branches and small trees in leaf begin to sway. Crested wavelets form on inland lakes and large rivers. |
6 |
Strong Breeze | 25 to 31 mph | Large branches in continuous motion. Whistling sounds heard in overhead or nearby power and telephone lines. Umbrellas used with difficulty. |
7 |
Near Gale | 32 to 38 mph | Whole trees in motion. Inconvenience felt when walking against the wind. |
8 |
Gale | 39 to 46 mph | Wind breaks twigs and small branches. Wind generally impedes walking. |
9 |
Strong Gale | 47 to 54 mph | Structural damage occurs, such as chimney covers, roofing tiles blown off, and television antennas damaged. Ground is littered with many small twigs and broken branches. |
10 |
Whole Gale | 55 to 63 mph | Considerable structural damage occurs, especially on roofs. Small trees may be blown over and uprooted. |
11 |
Storm Force | 64 to 75 mph | Widespread damage occurs. Larger trees blown over and uprooted. |
12 |
Hurricane Force | over 75 mph | Severe and extensive damage. Roofs can be peeled off. Windows broken. Trees uprooted. RVs and small mobile homes overturned. Moving automobiles can be pushed off the roadways. |
US Dept of Commerce
National Oceanic and Atmospheric Administration
National Weather Service
Portland, OR
5241 NE 122nd Avenue
Portland, OR 97230-1089
(503) 261-9246
Comments? Questions? Please Contact Us.