Origin of the expression "Snafu"

Factual Questions
1

What is the origin of the expression “Snafu”? Was this first used in WWII?

2

From the OED:

3

My understanding is that it is an acronym for “Situation Normal, All Fouled Up”, meaning a situation that has gone awry or deviated from plan. Not sure of the origin but I believe it was military in nature.

4

Other useful acronyms:
TARFU
FUBAR
BOHICA

5

Have you tried a dictionary?

Sounds like WWII indeed.

On preview I see that I’ve been beeten to the punch by RealityChuck, with the mighty OED even.
I wish to point out that I do believe that in this Merriam-Webster is better informed. I don’t think the F came from fouled, which the OED gives as primary explanation.

6

I was surprised, many years ago, to be told that the original form was not “Situation Normal All Fouled Up”, but Situation Normal All Fucked Up, as noted above. Then I read Allen Sherman’s book The Rape of the APE, where he gleefully noted his generation’s Coming of Age in the WWII Army. He says something like:
“Everything in the Army was obscene! Even the status reports contained terms like SNAFU (Situation Normal – All Fucked Up), JANFU(Joint Army Navy Fuck-Up), and FUBAR (Fucked Up Beyond All Recognition). (Back home they cleaned it up as “Fouled Up”).”

7

The other acronyms mentioned that haven’t been unacronymed are TARFU (Things Are Really Fowled/Fucked Up) and BOHICA (I had to look this one up-Bend Over, Here It Comes Again).