I grew up in Oklahoma and now live not too far from Joplin. I’ve seen worse from tornados. This is nothing really if you take into consideration the random body parts mixed with debris in a 60 mile radius of Joplin. My friends have gone down there to help and return with pictures more chilling than this.
Okay, this is one of the few times my job at a cement contractors’ office has come in handy: I asked one of our guys, and he said absolutely this could happen. Concrete is tested for strength all the time (at Texas A&M in this case), and one of the tests involves shooting 2x4s at concrete at 200 mph. Apparently a 2x4 will go through an 8” concrete wall like there’s nothing there. So with adjustments for the tornado wind speed, the narrower width of this curb and the size of the piece of wood, this is well within the realm of possibility.