I am pretty sure that I need a new alternator.
I got home from Death Valley last night and noticed that my radiator was leaking; so I took it out and soldered it. Since the radiator was out I washed the front of the motor and while I was rinsing things off with the garden hose the alternator started to smoke. The key was off so I disconnected the battery.
I put everything back together and now everything seems to be working except that the battery is not charging. The voltage across the battery terminals is dropping while the engine is running.
What in the alternator could short out like that with the key off?

 

Pretty sure that B+ terminal on alternator is always hot.
Properly functioning diode bridge inside alternator keeps current from backfeeding when engine is off.
Water must have shorted something. Alternator likely now dead.