How Wind Damage Is Measured (The 3 Official Wind Scales Used)

Wind damage – its dramatic impacts are sometimes the first images we see following a hurricane, tornado, or strong thunderstorm.

The dramatic effects of wind damage from a storm are usually the first images we see after a hurricane, tornado, or other strong storm.

Fortunately, meteorologists are constantly improving the forecasting methods — so homeowners, municipal leaders, and emergency officials can prepare for storms ahead of time and potentially prevent wind damage.

Where I live in Florida for example, hurricane season always means that city and county code enforcement officials are out in strong numbers:

Inspecting buildings for weak spots
Trimming down branches near utility lines
Reminding the public to upgrade their windows, entry doors, and garage doors to more wind-resistant varieties

Virtually all cities in Florida (and many places outside of the Sunshine State) are doing their best to comply with Miami-Dade County wind codes — which mandate some of the toughest hurricane wind codes in the world.

What makes wind codes from a county located in the southeast tip of Florida so special?

Well… it means that in order for your home to pass strict Miami-Dade wind codes, it must be able to withstand:

A 9-pound 2×4 being hurled toward it at 30 MPH
Being pelted by steel ball bearings traveling at a staggering 90 MPH

The 3 Wind Scales Used To Measure Damage

There are 3 primary wind scales that are commonly used to measure wind damage today.

Determining which of these scales is used depends on the type of wind damage that is being measured.

First, there is the Beaufort Wind Scale, which categorizes wind damage in incremental ranges up to hurricane force winds.

Then there is the hurricane category scale, called the Saffir-Simpson Hurricane Wind Scale. This scale divides hurricanes into 5 different categories, based on the highest average sustained wind speed for 1 minute of observed time.

Finally, there is the Fujita Tornado Damage Scale, which categorizes tornado wind strength based on observations of damage.

There are 3 official wind scales used to measure damage. Here's an explanation of each of them: the Beaufort Wind Scale, the Saffir-Simpson Hurricane Wind Scale, and the Fujita Tornado Damage Scale.

Let’s take a closer look at these 3 wind damage scales…

Beaufort Wind Damage Scale

In 1805, Sir Francis Beaufort devised a wind scale that determines approximate wind speeds based on observations of wind effects.

This wind scale includes the speed of the wind, the type of wind observed, and the actual conditions observed from the sea and from land.

Here is the Beaufort wind damage scale:

Wind Speed	Beaufort Number	Wind Description	Effects
Less than 1 MPH	0	Calm	Sea surface is smooth and smoke rises vertically.
1 to 3 MPH	1	Light air	Smoke drifts slowly with the breeze and indicates wind direction.
4 to 7 MPH	2	Light breeze	You can feel the wind on your face and hear leaves rustle.
8 to 13 MPH	3	Gentle breeze	Smoke moves horizontally and small branches sway.
14 to 19 MPH	4	Moderate breeze	Dust or sand on the ground will move and large branches will sway.
20 to 25 MPH	5	Fresh breeze	Surface waves form and small trees will sway.
26 to 31 MPH	6	Strong breeze	Trees bend with force and wind will whistle around utility wires.
32 to 38 MPH	7	Moderate gale	Large trees sway and moderate sea spray forms.
39 to 46 MPH	8	Fresh gale	Twigs break from trees and streaks of foam appear on the ocean.
47 to 55 MPH	9	Strong gale	Branches break from trees.
56 to 64 MPH	10	Whole gale	Trees are uprooted and the sea appears white.
65 to 74 MPH	11	Storm	Widespread damage occurs.
> 75 MPH	12	Hurricane	Structural damage occurs on land and strong waves form in the sea.

Saffir-Simpson Hurricane Wind Damage Scale

Hurricanes are among the greatest shows of Mother Nature’s strength. During the unleashing of their wrath, hurricanes can exert tremendous power that can wash away beaches & barrier islands, level towns, and devastate whole regions of a nation.

The hurricane wind scale was devised in 1971 by civil engineer Herbert Saffir and meteorologist Robert Simpson.

This wind scale divides hurricanes into 5 category strengths, based on wind speed.

Here are the 5 Saffir-Simpson hurricane categories:

Category	Wind Speed	Description
1	74 to 95 MPH	Weak hurricane
2	96 to 110 MPH	Moderate hurricane
3	111 to 129 MPH	Major hurricane
4	130 to 156 MPH	Major hurricane
5	157+ MPH	Major hurricane

Fujita Tornado Wind Damage Scale

Tetsuya Theodore “Ted” Fujita (aka Mr. Tornado) introduced the Fujita scale in 1971. Measuring wind speed AND correlating wind speed to wind damage, the Fujita scale is in widespread use around the world — not to mention the central United States, which is notoriously referred to as Tornado Alley.

The Fujita scale has been modified a few times over the decades — most recently in 2007, when attempts were made to more accurately match wind speeds to the severity of wind damage. (Since the adoption of the new wind measurement standards, the popular wind scale has been renamed the Enhanced Fujita Scale.)

This wind scale includes the speed of the wind and the type of wind damage observed.

Here are the current Fujita tornado wind speed standards:

Category	Wind Speed	Description	Damage Details
F0	40 to 72 MPH	Light damage	Branches broken off trees, sign boards pushed over
F1	73 to 112 MPH	Moderate damage	Mobile homes pushed off foundations, cars shoved off roads, garages severely damaged
F2	113 to 157 MPH	Significant damage	Roofs torn off homes, large trees snapped or uprooted, high-rise windows broken, mobile homes demolished
F3	158 to 206 MPH	Severe damage	Roofs and walls torn off homes, trains overturned, large cars lifted off the ground
F4	207 to 260 MPH	Devastating damage	Well-constructed homes destroyed, cars thrown like missiles, trees stripped of bark
F5	261 to 318 MPH	Incredible damage	Frame houses lifted off foundations and disintegrated, cars flung more than 100 yards, trees stripped of bark, steel-reinforced concrete structures damaged