i posted this to the plumbing forum also, i'm sorry for the duplicate posting, but i need help!

it figures these things always happen in the middle of the night and when my husband isn't home!!!! i was walking my dog out in the backyard this evening and heard a splish splashing noise coming from my crawlspace. i went under there and was able to see water pouring through my insulation underneath my house. the water coming out is warm water. the water is coming out from underneath the area of the house that has my hot water heater and spare bathroom. the hot water heater does not appear to be leaking, i do not have any water on the inside of my house, only underneath. i am assuming that i have a water pipe that has burst, but i am confused about something and please forgive my ignorance. i shut off the main water valve to the house, and the water has stopped pouring out of the insulation. since the water coming out is warm, then obviously the leak is after the water enters the hot water heater, probably in between the hot water heater and the spare bathroom. why would shutting off the main water supply stop the warm water leak, almost instantly? would it be because the water is no longer under pressure? since i no longer have any water flowing to my house at all, can i just shut off the hot water and still have cold water and hopefully no leak?(kids need to go potty in morning!) i'm feeling like an idiot here and sure need some guidance!