There is a cavern in my home town that I would likely go to if I heard the sirens go off. The main entrance would likely be locked but since the whole area is glenrose limestone, it's honey combed with caves and I could go to some that are less known. I would take my gear and get as deep in the cave as I could. Water wouldn't be an issue because it filters through the limestone so I would just need rations. I have tools that I could use to dig myself out incase of a collapse. I'm actually pretty experienced with caves so I have faith that I could stay in one for a while as long as I have a small scout tent and a wind up flashlight. What's your plan if you heard today that you might have an hour before a nuclear strike?