Spotter Information Page

Current Severe Weather Information

Reference Information

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Reference Information 

What makes a thunderstorm severe?

A severe thunderstorm is a thunderstorm that produces...

  • wind gusts of at least 58 mph (50 knots), and/or
  • hail at least 1 inch diameter (quarter size) and/or
  • a tornado

  Hail Size Chart: (diameter in inches) (visual chart)

  • Pea Size: 0.25 inches
  • Small Marble: 0.50 inches
  • Penny: 0.75 inches 
  • Nickel: 0.88 inches
  • Quarter: 1.00 inches <--Any hail this size or larger is severe thunderstorm criteria
  • Half Dollar: 1.25 inches
  • Ping Pong Ball: 1.50
  • Golf Ball: 1.75 inches
  • Hen Egg: 2.00 inches
  • Tennis Ball: 2.50 inches
  • Baseball: 2.75 inches
  • Grapefruit: 4.00 inches
  • Softball: 4.50 inches

Wind Speed Estimate:

  • 25-31 mph: Large branches in motion; whistling heard in telephone wires.
  • 32-38 mph: Whole trees in motion; inconveniencefelt walking against the wind.
  • 39-54 mph: Twigs break off trees; wind generally impedes progress.
  • 55-72 mph: Damage to chimneys and TV antennas; pushes over shallow rooted trees.
  • 73-112 mph: Peels surfaces off roofs; windows broken; light mobile homes pushed or overturned; moving cars pushed off road.
  • 113-157 mph: Roofs torn off houses; cars lifted off ground.



 Spotter Training Classes

Frequently Asked Questions about Spotter Training Sessions

  1. Do I need to preregister for these sessions? No. All you need to do is arrive at the proper time and location.

  2. About how long do the sessions last? Approximately 2 hours.

  3. Do I have to live / be a spotter in the county that I take the training session? No. The training sessions are identical.
  4. Is there online training I can review after attending the training course? Yes. You can find the online training at:

Below is a listing of upcoming severe weather spotter training sessions.


February, 2015 - Upcoming
Day City, State Time Location
28 Letts, IN
(Decatur County)
9:00am EST Fire Station; W Co. Rd 700S
28 North Vernon, IN
(Jennings County)
12:30pm EST Library; 2375 N. State Hwy 3

March, 2015 - Upcoming
Day City, State Time Location
02 Shelbyville, IN
(Shelby County)
7:00pm EST Indiana Downs; 4200 Michigan Rd
05 Indianapolis, IN
(Marion County)
2:00pm EST IUPUI; Campus Center Rm 405; 420 University Blvd
06 Bloomington, IN
(Monroe County)
7:00pm EST Hospital Auditorium; 2nd and Rogers St
07 Noblesville, IN
(Hamilton County)
9:00am EST Fire Station, 16800 Hazell Dell
07 New Castle, IN
(Henry County)
1:00pm EST Library; Indiana Ave & 15th St
10 Lebanon, IN
(Boone County)
7:00pm EDT County Sheriff; 1905 Indianapolis Ave
11 Anderson, IN
(Madison County)
7:00pm EDT Hoosier Park Racetrack, State Road 9
14 Indianapolis, IN
(Marion County)
9:00am EDT Integrated Public Safety Commission; 8468 E 21st
14 Danville, IN
(Hendricks County)
12:30pm EDT Hendricks Co. Govt. Center; 355 S Washington
16 Indianapolis, IN
(Marion County)
7:00pm EDT IUPUI; Campus Center Rm 405; 420 University Blvd
18 Greencastle, IN
(Putnam County)
7:00pm EDT 911 Dispatch; 1600W CR225 S
21 Spencer, IN
(Owen County)
9:00am EDT Spencer Christian Church, Montgomery & Market St
21 Brazil, IN
(Clay County)
12:30pm EDT Brazil Library; 204 N. Walnut St.
24 Rushville, IN
(Rush County)
6:00pm EDT 110 E. 13th St.; Rush Memorial Hospital Medical
26 Greenfield, IN
(Hancock County)
7:00pm EDT 1st Church of God; 700 N. Broadway
28 Kokomo, IN
(Howard County)
9:00am EDT Ivy Tech Center; 1500 N Reed Rd
28 Yorktown, IN
(Delaware County)
1:00pm EDT Yorktown Fire Dep't; 8905 W. Smith St. is the U.S. government's official web portal to all federal, state and local government web resources and services.