How to Identify a Funnel Cloud

According to dictionary.com, a funnel cloud is "a rapidly rotating funnel-shaped cloud extending downward from the base of a cumulonimbus cloud, which, if it touches the surface of the earth, is a tornado or waterspout."

In order to accurately identify a funnel cloud, it is helpful to have a basic understanding of cumulonimbus clouds and wall clouds.

A cumulonimbus cloud is "a dark cloud of great vertical extent charged with electricity" A cumulonimbus cloud is also known as a "thundercloud".

A wall cloud, or pedestal cloud, which is a large, low-hanging cloud at the base of a cumulonimbus cloud, marks the area of the strongest updraft. Funnel clouds are typically seen extending downward from a wall cloud.

Keeping these basic definitions in mind, follow the easy steps below to correctly identify a funnel cloud.

Difficulty: Moderately Easy

Instructions

1. 
   False Alarm! (See Resources Section Below for More Photos of False Alarms on the NOAA Website)

   Is there a thundercloud?
   
   A cumulonimbous cloud or thundercloud will most likely be present in order for conditions to be right for a funnel cloud to form. Clouds make all sorts of formations and take on all shapes and sizes. This can fool the casual observer into thinking he sees something he does not. A completely harmless rain cloud can be mistaken for a vicious killer in the making to the untrained eye. Without the presence of a thundercloud or wall cloud, you have nothing to fear.

2. 
   Wall Cloud

   Do you see rotation?
   
   Rotation is a must for a funnel cloud. If there is no rotation, there is no funnel cloud.

3. 
   Intense Rotation and Downward Extension

   Watch out for downward extension!
   
   Once you see downward extension from a mischievous-looking rotational cloud with a thundercloud or wall cloud also present, get far, far away. That is, of course, unless you are much like the author, in which case you will get much closer and ask it for an autograph. It is about to change its name to "Tornado".

Resources

• False Alarm Funnel Clouds
• Tornado and Funnel Cloud images

[pinchy]

on 11/20/2009 great tips for identifying a funnel cloud!

[pinchy]

on 11/20/2009 great tips for identifying a funnel cloud!

[emilymurray]

on 11/19/2009 Great pic's and interesting article. Excellent work!

[mrhow-to]

on 10/12/2009 Good article, I like storms and have always wanted to see a tornado. 5*

[mfrussell]

on 10/10/2009 This is such a great article. I am terrified of tornadoes and think all clouds are funnel clouds. This will definitely put my mind at ease now! 5* and a recommend!!