I've always done summer hiking in the Sierra without bringing rain gear, but others here have asserted that I'm asking for trouble by assuming that whatever was OK in past, typical conditions will be OK in the future. Considering that any rain gear I bring will be 99% likely to sit in the pack without being used, I'd like to minimize weight and bulk. I have a bunch of 18-gallon, 2.5-mil trash compacter bags, and I've found that I can make a poncho that fits my torso out of one of these. As an added bonus, I look stylish as hell in it.
But now I have the following things in my kit that seem at least somewhat redundant:
-ground sheet, 3.4 oz
-bag for use as pack liner, 2.5 oz
-bag for use as emergency poncho, 2.5 oz
Can anyone think of any way of reducing this to two items instead of 3? If I'm caught in the mother of all summer storms, I don't want to cannibalize my pack liner for use as a poncho, because then my down bag will get wet. If I cut a head-hole in the ground-sheet, I'd have some kind of poncho, but it would probably flap like crazy in the wind, and my groundsheet would then have a big hole in it, although I guess I could save the cutout circle and patch it back on with duct tape.
Ideas?

