Overview
See this NWS Skywarn page.
| Event | Document And Description |
|---|---|
| Tornado: | Is it rotating ? If not, it’s a rain shaft.
Is it in contact with the ground ? If Not, it’s a Funnel Cloud. |
| Funnel Cloud: | Is it rotating? Is it in contact with the ground? If so, it’s a Tornado. Is The Occurrence Now? Past? Just Beginning? Where Is The Location? |
| Wall Cloud: | Is The Occurrence Now? Just Beginning? How long observed? Is it rotating? Where is the Location? |
| Severe Winds: | What type and kind of severe wind damage ? Use the Beaufort Wind Speed Chart When is the occurrence Now ? Past ? Just Beginning ? Where is the Location ? General Examples of Severe Wind Damage: Power lines blown down. Windows broken by wind Permanent signs blown down. Radio tower/large antenna blown down Mobile home damaged. Large roof area damaged Structure damage to buildings by winds. More than one large tree blown over |
| Hail: | Do not use “Marble” size When is the occurrence Now – on going event ? Where is the Location ? What Size Hail Stones. How Large? Pea…………..1/4 inch. Dime…………3/4 inch. Nickel………..7/8 inch. Golf ball…….1 inch Quarter…….. 1 inch. Baseball…….2 1/4 inch. Softball………3 to 4 inch And if in Western and Northern Texas…cantaloupe…basketball |
| Flash Flooding: | What do you see? How Deep, and How Extensive? Are the animals walking two by two?? Is there a immediate threat to persons or property? When is the occurance? On Going or Just Beginning? Where is the Location? |
| Rain: | When did the severe rain start, Now or Just Beginning? Is it so heavy, you can’t drive? Where is the Location? How Much Rain? At a rate of 2 inches per hour? |
Estimating Hail Size(NWS)
| Hail Diameter | The Physical Description |
|---|---|
| 1/4″ | Pea Size |
| 1/2″ | Marble Size (say “half-inch”) |
| 3/4″ (Severe Criteria) | Dime Size |
| 7/8″ | Nickel Size |
| 1″ | Quarter Size |
| 1 1/4″ | Half Dollar Size |
| 1 1/2″ | Walnut or Ping Pong Ball Size |
| 1 3/4″ | Golf Ball Size |
| 2″ | Hen Egg Size |
| 2 1/2″ | Tennis Ball Size |
| 2 3/4″ | Baseball Size |
| 3″ | Teacup Size |
| 4″ | Grapefruit Size |
| 4 1/2″ | Softball Size |
Estimating Wind Speeds
| Wind Speed | The Effects |
|---|---|
| 25-31 | Large branches in motion; whistling heard in telephone wires |
| 32-38 | Whole trees in motion; inconvenience felt walking against the wind |
| 39-54 | Twigs break off trees; wind generally impedes progress |
| 55-72 | Damage to chimneys and TV antennas; pushes over shallow rooted trees |
| 73-112 | Peels surfaces off roofs; windows broken; light mobile homes pushed or overturned; moving cars pushed off road |
| 113-157 | Roofs torn off houses; cars lifted off ground |