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2025 Hazard Mitigation Plan <br />Kittitas County, Washington <br /> <br /> <br />Chapter 4: Hazard Identification and Risk Assessment 159 <br />Hail Size <br />(inches) Object Analog Reported <br />4.50 Grapefruit <br /> <br />The Beaufort Wind Scale was developed to estimate and report wind speeds when a measuring <br />apparatus is not available (e.g, open sea). It was invented in the 1805 by Sir Francis Beaufort of the <br />British Navy as a way to interpret wind conditions at sea. Since then, the scale has been modified to <br />include the effects on land. Table 4-98 outlines the 13 force classification that comprise the Beaufort <br />Wind Scale.201F <br />201 <br />Table 4-98. Beaufort Wind Scale <br />Force Wind <br />(knots) Classification Appearance of Wind Effects <br />On the Water On Land <br />0 < 1 Calm Sea surface smooth and mirror- <br />like. Calm, smoke rises vertically. <br />1 1 – 3 Light Air Scaly ripples and no foam crests. Smoke drift indicates wind direction <br />and still wind vanes. <br />2 4 – 6 Light Breeze Small wavelets, crests glassy, and <br />no breaking. <br />Wind felt on face, leaves rustle, and <br />vanes begin to move. <br />3 7 – 10 Gentle Breeze Large wavelets, crests begin to <br />break, and scattered whitecaps. <br />Leaves and small twigs constantly <br />moving, and light flags extended. <br />4 11 – 16 Moderate <br />Breeze <br />Small waves of one (1) to four (4) <br />feet becoming longer with <br />numerous whitecaps. <br />Dust, leaves, and loose paper <br />lifted, and small tree branches <br />move. <br />5 17 – 21 Fresh Breeze <br />Moderate waves of four (4) to eight <br />(8) feet taking longer form, many <br />whitecaps, and some spray. <br />Small trees and leaves begin to <br />sway. <br />6 22 – 27 Strong Breeze <br />Larger waves of eight (8) to 13 feet, <br />whitecaps are common, and more <br />spray. <br />Larger tree branches moving and <br />whistling in wires. <br />7 28 – 33 Near Gale <br />Sea heaps up, waves are 13 to 19 <br />feet, white foam streaks off <br />breakers. <br />Whole trees moving and resistance <br />felt walking against wind. <br />8 34 – 40 Gale <br />Moderately high waves (18 to 25 <br />feet) of greater length, edges of <br />crests begin to break into spindrift, <br />and foam blown in streaks. <br />Twigs breaking off trees and <br />generally impedes progress. <br />9 41 – 47 Strong Gale <br />High waves (23 to 32 feet), sea <br />begins to roll, dense streaks of <br />foam, and spray may reduce <br />visibility. <br />Slight structural damage occurs, <br />and slate blows off roofs. <br />10 48 – 55 Storm <br />Very high waves (29 to 41 feet) with <br />overhanging crests, sea white with <br />densely blown foam, heavy rolling, <br />and lowered visibility. <br />Seldom experienced on land, trees <br />broken or uprooted, and <br />considerable structural damage. <br />11 56 – 63 Violent Storm <br />Exceptionally high waves (37 to 52 <br />feet), foam patches cover sea, and <br />visibility more reduced. <br />-- <br /> <br />201 National Weather Service. (n.d.). Beaufort Wind Scale. Retrieved from <br />https://www.spc.noaa.gov/faq/tornado/beaufort.html.