Ok just checking. Shorts as you know can happen at any time, just from a bump to the guitar or amp. Have you checked to make sure the speaker wires inside the cab are all connected. Could be one of the spade connectors jiggled loose.
Also, have you tried turning each pot to make sure none are scratchy? If one is, turn it back and forth fast several times to try to clear out the dirt and/or use some De-Oxit. Perhaps there's some corrosion inside the pot or on one of the lead ends
http://www.caig.com/
Also, George L's could be the culprit if the lead was still plugged into the amp but not the guitar. Worst cable I ever used and not reliable at all for road use IMO. The screw holding the ends on almost always comes loose and shorts out and needs re-connected especially if you have to plug and unplug it a few times. Try a different cable like a Lava if you really want a reliable, better sounding and less noise than the George L cable
http://www.lavacable.com/ I stuck my shorted out L's in the drawer after getting tired of fixing them.