Cancel a snapshot delete in progress?

There are a thousand threads around the internet about why snapshot deletion takes so long. I get that.

Here's the thing. I've got a snapshot that's been deleting for a little under 24 hours. Still going. And in another few hours (sometime tonight - not sure exactly when), the power for the office complex I'm in is going to be shut down for some sort of maintenance.

Is there a way to cancel the delete? What are the consequences of the computer shutting off in the middle of a snapshot deletion operation? I knew it took a while, but I didn't know it took THIS long.

Thanks in advance.