A violently rotating column of air extending downward from a thunderstorm base that is in contact with the ground, causing swirls of dust, debris, and condensation. Note: Even if in ground contact, the tornado’s funnel bounds may not be visible.


A rotating, funnel-shaped cloud extending downward from a thunderstorm base, but is not in contact with the ground, as indicated by the absence of dust or debris.


A large, cylindrical cloud structure that is lowering from the thunderstorm’s rain-free base and exhibiting persistent, sustained rotation and/or rapid vertical motion.


Penny size or larger, which is typically associated with severe thunderstorms. Report the largest size hailstone observed. (See charts below for size references.)


40 mph or higher for 5 seconds is reportable. Specify whether speed is estimated or measured. (See chart below for guidelines in estimating wind speed.)


Usually happens within 6 hours of the rain event or because of a dam or levee failure. Most often located at “funneling” points of smaller streams or rivers.

RAINFALL > 1″ / hr.

Typically associated with severe thunderstorms. May be accompanied by hail.

30-44 mph (26-39 kt)

Whole trees in motion. Inconvenient walking into the wind. Lightweight 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 or 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.


.25 inch

Golf Ball

1.75 inch


.50 inch

Pool Ball / Hens Egg

2.00 inch

Penny / Dime

.75 inch

Tennis Ball

2.50 inch


.88 inch


2.75 inch


1.00 inch

Tea Cup

3.00 inch

Half Dollar

1.25 inch


4.00 inch

Ping Pong Ball

1.50 inch


4.50 inch

  • WHO – Give your call sign and current fixed/mobile location.
  • WHAT -Tornado, funnel cloud, rotating wall cloud, quarter size hail, flash flooding, etc. Describe the storm or event’s direction and speed of travel, size and intensity, and destructiveness. Include any amount of uncertainty as needed, i.e., “funnel cloud; no debris visible at the surface, but too far away to be certain it is not on the ground.”
  • WHERE – To avoid confusion, report the severe weather event location and not your location. Give the direction and distance from a known, easily fixed position. Reports that include a cross street or distance and direction from a cross street where spaced further apart are best, e.g., “1/2 mile east of Jackson Trail and Highway 53.”
  • WHEN – Make sure you note the time of your observation (not the time you report it).

The following procedure is recommended when making a severe weather report during any weather event on the frequency for the Hall County Skywarn Net. Collecting accurate, timely information from spotters is vital. Lives could be at stake, so exercise discipline at all times and employ good operating practices during the net. Remember, this will be a formal, directed net. As a good net participant, much of your time will be spent monitoring the frequency rather than transmitting. Only call the NCS when directed to or if you have relevant traffic.

Important points to remember when making a report:

  • Be sure of your observation (use measured reports for wind speed, rain, etc., when available).
  • Take a moment to formulate your report before keying the microphone. Be sure that you have all the required information.
  • Be sure to include the type of event you are reporting during your initial contact. This helps the NCS prioritize reports that may come in at the same time.
  • If mobile, know your location at all times. This is as much for your own safety as it is for reporting accuracy.
  • Once phenomena has been identified and determined to match severe weather criteria, the spotter should call net control indicating a severe weather report, e.g., “This is with a hail report.” Wait for acknowledgment from the NCS, continue with your location, and provide a concise description of the severe weather observed, including its movement and location. Use the “4 W’s” method of reporting as described above: “Who, What, Where, When.”
  • Example: “This is located in Clermont on Highway 129 and Highway 284, reporting golf ball size hail observed at 11:13 local time. I am watching a funnel cloud form at the base of a thunderstorm approximately 3 miles west of my location. The funnel cloud appears to be moving east-southeast. No debris is visible at the surface.”
  • Example: “This is located in Candler at Highway 211 and Highway 60 reporting a tornado observed on the ground 2 miles west of my location at 9:42 local time. The tornado is moving east.”

  • Reporting Tools

    NWS Submit Report
    NWS – 866-763-4466


    Hall County Skywarn sends out notifications when we move to elevated conditions.

    Notifications can be sent to either your email or to a cell phone number, or both if you prefer.

    If you would like to have notifications sent to you, please send an email to with your name and Amateur call sign (if applicable), and the email and/or phone number where you wish to receive notifications.