Milwaukee Skywarn Scale for Storm Spotters

Hail Reference Chart

Report The Largest Size Observed And Any Hail Covering The Ground. 
MEASUREMENTS:  Measure The Outside Diameter, The Longest End-To-End Axis.

Size Description
1/4-3/8"    Pea Size
1/2"     Small Marble Size
3/4" Penny Size
7/8" Nickel Size
1" Quarter Size
1 1/4" Half Dollar Size
1 1/2" Walnut/Ping Pong Ball Size
1 3/4" Golf Ball Size
2" Lime/Hen Egg Size
2 1/2" Tennis Ball Size
2 3/4" Baseball Size
3" Large Apple
4" Softball Size
4 1/2" Grapefruit Size
4 3/4" - 5" Computer CD / DVD Size
8" US Record

The Hail chart applies only to the counties served by the NWS Milwaukee/Sullivan office: 
Milwaukee, Racine, Kenosha, Walworth, Waukesha, Ozaukee, Sheboygan, Washington, Fond Du Lac, 
Rock, Green, Lafayette, Iowa, Dane, Dodge, Columbia, Marquette, Green Lake, , Richland, Sauk

Wind Speed Estimates

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 1-3 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 4-7 MPH Wind felt on face. Leaves rustle and small twigs move. Ordinary wind vanes move.
3 Gentle Breeze8-12 MPH Leaves and small twigs in constant motion. Wind blows up dry leaves from the ground. Flags are extended out.
4 Moderate Breeze13-18 MPH Wind moves small branches. Wind raises dust and loose paper from the ground and drives them along.
5 Fresh Breeze 19-24 MPH Large branches and small trees in leaf begin to sway. Crested wavelets form on inland lakes and large rivers.
6 Strong Breeze 25-31 MPH Large branches in continuous motion. Whistling sounds heard in overhead or nearby power and telephone lines. Umbrellas used with difficulty.
7 Near Gale32-38 MPH Whole trees in motion. Inconvenience felt when walking against the wind.
8 Gale 39-46 MPH Wind breaks twigs and small branches. Wind generally impedes walking.
9 Strong Gale 47-54 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 Gale55-63 MPH Considerable structural damage occurs, especially on roofs. Small trees may be blown over and uprooted.
11 Storm Force 64-75 MPH Widespread damage occurs. Larger trees blown over and uprooted.
12 Hurricane ForceOver 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.

All references to trees are for trees with foliage. Significantly higher winds may be required to cause similar damage to trees without foliage. Also, very wet soil conditions may allow weaker winds of 30-57 MPH to uproot trees.

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