Like a bomb went off under the hood...

AJ makes a god point about the clamp. I bet either it failed, OR what I see ALL the time, the clamp was improperly positioned. I see people all the time put the clamp ON TOP of the hose barb and not behind it. Why they do this, I have no idea. If you position the clamp behind the hose barb and tighten it up good the only way it will come off is if the hose tears. Even then, it will leave the part of the hose clamped to the hose barb.