This is a very interesting, and very preliminary, report from the American Meteorological Society on the fatalities associated with the El Reno, OK tornado of May 31, 2013. While the final report should be forthcoming soon, this is still a very informative, and humbling, read.
Before downloading, please keep in mind that this is a forty-four page PDF file.
The report is very detailed and is quite technical. The basic message behind the report is that the El Reno tornado was rather rare in its structure, behavior, and life cycle. As an interesting side note, a similar storm mentioned on page sixteen that occurred near Geary, OK in May, 2004 is a tornadic supercell that I recall very well due to my own close encounter. Like the El Reno/Canadian County, OK supercell, the structure was largely High Precipitation (HP) in nature and more than once I found myself in a potentially dangerous setting when attempting to get a clearer view of the wall clouds and tornadoes.
I hope to see further research into the El Reno event in the future if for no other reason that it was a structurally unique tornado. Fortunately, most tornadic supercells aren’t similar to this event. Regardless, there’s never enough that we can learn about unusual storms of this nature.