Imagine the subterranean pressure that would be required to have reached a critical point for ALL of them to 'fountain forth' at once!
In reading some of the ancient stories from other cultures regarding the Flood, I was fascinated to find that several of them refer to the erupting waters as scalding, burning everything. Think Yellowstone, magnified exponentially.
Pressure and heat go together.
Which is why I am thinking that those torrential rains of that time were not from a vapor canopy, but primarily from the condensing waters as they hit the cooler air above. The 'rain' would not only have been water but have involved massive amounts of pulverized debris.
What is interesting is that this is exactly what we see BELOW the Cambrian strata -- an enormously deep debris layer covered by a mile or so of carbon-rich sediments. That is our Flood. The fossils came later. I doubt seriously if Noah's Flood could have fossilized anything.