Well, a couple folks beat me to it, but looking at the photo, my first reaction was, "OMG"... about the wire and the plug along the fence. Wire used outside should be rated for outside use, in a conduit or the type that's buried under ground with it's own weather proof insulation. (not cheap either). The electric box is not proper for outside use either. It doesn't look like an RV receptacle. Reminds me of a box that would be used inside to plug in an electric welder or some such device that takes 220 electricity, not intended for outside. This was definitely a disaster waiting to happen.
You are correct in the fact there was not enough height in the plug for the adapter to hang. Laying on the ground would allow water, even dew and humidity to seep into the plug prongs and cause a short out. It would be like laying the connection in a bucket of water. Hanging, water would drip off.
I am glad nothing more was damaged. This could have had a totally different and a horrible end had your wife not been right there and responded quickly.
But, here is your chance to fix it all correct now. I'm glad you and your home are OK.