For alpine trips where you expect high winds and a flat level spot bigger than a bivy is rare then a bivy works great. I have spent some time on exposed narrow ridges sleeping in a bivy and it worked great.

A bivy works great in a snow cave.

Most of the time hammock under a good tarp works best for me.
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"In theory, theory and practice are the same. In practice, they are not."
Yogi Berra