There are quite a few people who can essentially snore while awake if they have had a decent amount to drink. However, the same people are completely unable of replicating said snoring if they are sober - it’s just beyond them.
What is the cause of this?
I’ve been tested for sleep apnea (basically snoring) and was told that the muscles in your neck relax when you sleep and that it can trigger one of the mechanisms that allows for snoring to occur. With enough alcohol I suspect the muscles can relax enough to trigger snoring as well.
Alcohol relaxes muscles in general; the soft palate in this case.