How to estimate wind speeds

918 reads

By David Silver on April 10, 2012, 3:12am

Use your ← → (arrow) keys to browse more stories.

This month of April seems more like March with the high winds we have been experiencing all week. My anenometer measured a wind gust of 25 mph today. But without a wind gauge how could we tell what kind of wind speeds we have been having? Well, thanks to Francais Beaufort, we have a standardized way of telling what the wind speeds are without having to have a anenometer on hand. Beaufort came up with a way of standardizing wind speeds in 1805. Now, with this Beaufort scale we can gauge wind speeds by observaton without an instrument on hand. Here is a abbreviated list of the Beaufort scale. The scale has been modernized.

Wind Speed in mph, Beaufort number, Wind Effects on Land

Less than 1 0 Calm, smoke rises vertically

1-3 , 1 Wind direction is seen in direction of smoke

4-7 2 Wind can be felt on face, leaves rustle

8-12 3 Leaves and small twigs in motion, wind extends a light flag

13-18 4 Wind raises dust and loose papers. Small branches move.

19-24 5 Small trees with leaves begin to sway, crested wavelets appear on inland waters

25-31 6 Large branches move, umbrellas become difficult to control

32-38 7 Whole trees sway and walking into the wind becomes difficult

39-46 8 Twigs break off trees, cars veer on roads

47-54 9 Slight structural damage occurs, roof tiles may blow away

55-63 10 Trees uprooted, considerable structural damage is caused

64-72 11 Widespread damage is cuased

73 + 12 Widespread damage.

While out in the gardens today, I guessed at a Beaufort number of 4 which would have indicated wind speeds of 13-18 because of the raising dust and branches moving in the trees. On my way home, I noticed the wind pushing up the waves on Bantam Lake so I upped my estimate to 19-24 mph and a Beaufort number of 5. First thing at the house, I checked the memory on the wind gauge and it had indicated a wind gust of 25 mph. That's pretty accurate.

Next windy day, try out this Beaufort scale and check your observations by your own anenometer or the weather newscast on News8.

Use your ← → (arrow) keys to browse more stories.