Yes, huge.
What creates them is a big mystery.
I would think that unless the water is very hot and under a lot of pressure, it would freeze before ever getting to the surface. So, what’s creating the heat? Stress from Saturns gravity or other moons maybe?
...And where does the water come from in the first place? Ice I’m sure, but where does the ice come from? You have to have water, before ice can form.
Very interesting.