Ducknut taught me the plastic bag anchor method a couple of years ago on Rainier and I've used it ever since. If you don't trust the handles, fill them with snow and tie your guyline around the bag.
Or, if there's rocks handy, tie your guyline around a rock & bury it. Works just as well.
The only problem I have is not wrecking the cord when I'm digging out. But cord's replaceable.