looking for Sci-Fi book about a modern-day Flood

I have googled and such to no avail, so I hoped that joining a forum such as this would help me find this book.

I read it as a child in the mid-to-late 1970s upon finding it lying around in my parents' library. (long gone now of course)

All I remember is parts of the plot line. These two greaseball characters somehow discover that the freak rainstorm is actually a new worldwide Flood coming, so they obtain a motorhome and set out across America looking for higher ground, looking for others (women) to take with them to escape the flood and start a new life. Along the way they pick up a pregnant scientist who is terrified of sex, a male cross-dresser who uses a hat-pin for a weapon, and a 12-year old girl (among others). The novel had lots of references to the biblical Flood of course, and supposedly this modern flood was caused by Man experimenting with weapons technology out in space. There was something about a quadruple rainbow, too. The book examines the complex interpersonal relationships between this group of strangers facing a common enemy (the flood) together.

If anyone can tell me the name of the book or the author I'd really appreciate it!!

Thanks,
Ianski

Your question, with no responses, came up first when I googled a description of the book. Original question was posted 9 years ago so I doubt the OP will see this but just in case someone else is looking for this book here is the answer: Ring of Ice by Piers