I tried to shut off the water to stem the tide, only to find that, at 5'1", I am ill-suited to reaching the valve on top of a 50-gallon water heater. I made 5 or 6 tries at it, but no go. Got my white Oscar Wilde t-shirt thoroughly drenched, though, by repeatedly pressing myself snugly up against the waterfalling water heater ... so at least I put on a show for the neighbors.
Upon phoning our usual plumber I was informed that they would not be able to send someone out to fix it until Monday.
Luckily, the hubby's job is flexible enough that he was able to race home to shut off the water. (Damn! I hate being short at times like this!) And upon making a couple more phone calls, I found a plumber who will be able to come out tonight. So it looks like we won't actually be facing a holiday weekend with no hot water.
Of course, now we have to wait for the plumber to arrive ... and see if this metal shed is easily dismantled (in the dark, since we have no lights in the backyard) to install a new water heater. Oh joy.