What Happens When You Freeze an Island and then Explode It?

In the first of the Sir William & Mac Life Without Slippers Series, The Mac, the evil ice queen, Bax, is trying out her new ship's capabilities to freeze, and her favorite part, explode.
This is a quote from Sir William as he talks to the Assembly of Fidea about Bax:

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"We all know she’s back. We don’t just have islands freeze and explode for no apparent reason, do we? Can we in any way call it normal? It’s Bax.
“Now, Kenny boy, you sniveling trail of snail snot, here’s a thought, why don’t you get out your brand new, expensive space buggy and go after her yourself?”
Kenny squirmed. “I think the most prudent thing to do, at this time, is to appoint a special investigator, no, wait, a committee, to asses her activities and degree of potential damage..."
“Investigate possible threat? What a novel, brilliant thought. Let’s back up and go over what we know so far. She can ice an entire planet! Hmmm. That might be a threat. Ya’ think? She can kill all living creatures on it, and will not even break a sweat!"

In researching what an exploding, ice island would look like in the sky I found this great article from Wired: Weird Rare Clouds.

This spectacular photo of the eruption of Sarychev Volcano in the Kuril Islands, northeast of Japan on June 12 shows an interesting example of a pileus cloud. The ash plume appears to have a smooth white cap on it as it breaks through the cloud cover above.

Bad, bad Bax