Although reporting criteria may vary slightly depending on the spotter network and local needs, these are the events the National Weather Service would like to know about as soon as possible:
FUNNEL CLOUD: Organized, persistent, sustained rotation
WALL CLOUD: Organized, persistent, sustained rotation
HAIL: Quarter size or larger – Report the largest size hailstone
WIND GUSTS: 58 mph or higher – Specify estimate or measurement
FLOODING: Flooding that impacts roads, homes or businesses.
Damage to structures (roof, siding, windows, etc)
Damage to vehicles (from hail or wind)
Trees or large limbs down
Power/telephone poles or lines down
Damage to farm equipment, machinery, etc
Again, reports should provide as much detail as possible to describe the where, when, how, etc of the event.
Some commonly used hail reporting sizes:
Pea .25 inch
Half-inch .50 inch
Dime .75 inch
Nickel .88 inch
Quarter 1.00 inch
Half Dollar 1.25 inch
Ping Pong Ball 1.50 inch
Golf Ball 1.75 inch
Hen Egg 2.00 inch
Tennis Ball 2.50 inch
Baseball 2.75 inch
Tea Cup 3.00 inch
Grapefruit 4.00 inch
Softball 4.50 inch
General Guidelines for Estimating Wind Speeds
30-44 mph (26-39 kt) Whole trees in motion. Inconvenient walking into the wind. Light-weight loose objects (e.g., lawn furniture) tossed or toppled.
45-57 mph (39-49 kt) Large trees bend; twigs, small limbs break and a few larger dead or weak branches may break. Old/weak structures (e.g., sheds, barns) may sustain minor damage (roof, doors). Buildings partially under construction may be damaged. A few loose shingles removed from houses.
58-74 mph (50-64 kt) Large limbs break; shallow rooted trees pushed over. Semi-trucks overturned. More significant damage to old/weak structures. Shingles, awnings removed from houses; damage to chimneys and antennas.
75-89 mph (65-77 kt) Widespread damage to trees with large limbs down or trees broken/uprooted. Mobile homes may be pushed off foundation or overturned. Roof may be partially peeled off industrial/commercial/ warehouse buildings. Some minor roof damage to homes. Weak structures (e.g., farm buildings, airplane hangars) may be severely damaged.
90+ mph (78+ kt) Many large trees broken and uprooted. Mobile homes damaged. Roofs partially peeled off homes and buildings. Moving automobiles pushed off the road. Barns, sheds demolished.
HOW TO REPORT
Your severe weather report should be detailed but concise, and should address the following questions:
WHAT did you see?
WHERE did you see it? Report the location/approximate location of the event. Be sure to distinguish clearly between where you are and where the event is thought to be happening (“I’m 5 miles north of Mayberry. The tornado looks to be about 5 miles to my northwest”).
WHEN did you see it? Be sure that reports that are relayed through multiple sources carry the time of the event, NOT the report time.
Any other details that are important – How long did it last? Direction of travel? Was there damage? etc.
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