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2025 Hazard Mitigation Plan <br />Kittitas Gounty, Washington <br />Grapefruit4.50 <br />Hail Size Object Analog Reported <br />The Beaufort Wind Scale was developed to estimate and report wind speeds when a measuring <br />apparatus is not available (e.9, open sea). lt 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.-2ol <br />Table 4-98. Beaufort Wind Scale <br />201 NationalWeather Service. (n.d.). Beaufort Wind Scale. Retrieved from <br />https ://www.spc. noaa. qov/faqltornad o/beaufort. htm l. <br />0 <1 Calm Sea surface smooth and mirror- <br />like.Calm, smoke rises vertically. <br />Smoke drift indicates wind direction <br />and stillwind vanes.1 1-3 Light Air Scaly ripples and no foam crests <br />2 4-6 Light Breeze Small wavelets, crests glassy, and <br />no breakinq. <br />Wind felt on face, leaves rustle, and <br />vanes beqin to move. <br />Large wavelets, crests begin to <br />break. and scattered whitecaps. <br />Leaves and small twigs constantly <br />movinq. and liqht flaqs extended.3 7 -10 Gentle Breeze <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 />17 -21 Fresh Breeze <br />Moderate waves of four (4) to eight <br />(8) feet taking longer form, many <br />whitecaps. and some sprav. <br />Small trees and leaves begin to <br />sway.5 <br />6 22-27 Strong Breeze <br />Larger waves of eight (8) to 13 feet, <br />whitecaps are common, and more <br />sprav. <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 />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.B <br />9 41 -47 Strong Gale <br />High waves (23 lo 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 />48-55 Storm <br />Very high waves (29to41feet) with <br />overhanging crests, sea white with <br />densely blown foam, heavy rolling, <br />and lowered visibilitv. <br />Seldom experienced on land, trees <br />broken or uprooted, and <br />considerable structural damage. <br />10 <br />11 56-63 Violent Storm <br />Exceptionally high waves (37 lo 52 <br />feet), foam patches cover sea, and <br />visibility more reduced. <br />Wind <br />(knots) <br />Appearance of Wind Effects <br />J .rl t' <br />Force Classification <br />1 jI ilir(r Y.r,ill;lriri <br />Chapter 4: Hazard ldentification and Risk Assessment 159