Anyone who has taken an organic chemistry course should know that this can happen with most liquids if they are not heated evenly. That's why organic chemists use boiling stones:
Boiling stones have tiny air bubbles trapped in them, which somehow aids nearby hot water to change phases when it gets hot enough.
I've personally heated a liquid on a steam bath, picked up the glassware to swish the liquid around and had it rupture all over my hands. Why? Because I didn't use boiling stones -- shaking it caused part of the liquid to suddenly change phases into gas. I think you can achieve the same effect as boiling stones using salt if you're heating water, but I'm not totally sure.
Here's some more on 'exploding' water at Snopes.com: