Shelf cloud vs. Wall cloud: Part Deux

Due to an overwhelming response to the Weather 101: Shelf cloud vs. Wall cloud post, I’ve decided to post some additional shelf cloud and wall cloud examples that were supplied to me with permission by fellow weather enthusiasts to illustrate proper cloud identification.

Each cloud type has different characteristics to provide clues as to what kind of weather can be expected in the short-term, so accuracy is important.  As discussed in the original post, an approaching shelf cloud is a strong indication of very gusty straight-line winds that can pose a safety hazard.  Straight-line winds have been known to reach or exceed 100 MPH, which is equivalent to an EF-1 tornado!  A nearby wall cloud means residents should be prepared to take cover.  Wall clouds are typically rotating, and are sometimes a pre-cursor to funnel clouds, which may eventually produce a tornado if the funnel extends all the way to the ground.

Wall cloud examples:

 Michael Thompson took this photo of a wall cloud near Crookston, MN on July 4, 2011.  Notice the distinct lowering of the cloud base.  (For great storm photos, I recommend following Michael’s blog.  His photos are professional, high quality.)

Wall cloud approaching downtown St. Paul, Minnesota from June 21, 2011. Video by David Blume, KD0IRF.

Shelf cloud examples:

 Michael Thompson took this photo of a shelf cloud rolling in near MSP airport on July 1, 2011.

Video shot by Michael Thompson of a shelf cloud approaching MSP airport on July 1, 2011.

As I was discussing this matter with Michael, he pointed out that a shelf cloud looks like a huge wall coming at you.  This is very true, and a big reason why the mistake in identity happens.  Hopefully, this additional media makes it easier to understand the differences between a shelf and wall cloud, so when severe weather occurs close to your neighborhood, you will know what kind of weather to expect!  I would like to personally thank Michael and David Blume for their outstanding contributions on this topic.  It’s amazing what a little collaboration and help among weather enthusiasts can do.  We all learn from each other, and in turn, it becomes a tighter knit group.  I cherish what I have learned from weather spotters, chasers, and enthusiasts that I have encountered over the last few years.  It’s truly amazing.

RS