Editing 1038: Fountain

From the first panel (and assuming that [[Cueball]] is of average height) - it looks like the center fountain is about 10m high.  By comparison with the size of his head in the second panel, the jet appears to be about 10cm in diameter. The velocity of the water exiting the nozzle has to be about 14 meters/second in order to reach 10m against gravity.  If we approximate the nozzle as being a 10cm x 10cm square - that translates to 140 liters/second - or 140kg/s of water.  That produces an upward force of almost 2,000 newtons! If we presume that [[Cueball]] weighs 100kg (~1,000N)- he should be experiencing a net upward force of about 1,000N.  Which means that he'll accelerate at about 1g!  Holding onto the umbrella against a force of 1g is very different to hanging by your hands from a horizontal bar, since you would actually experience two gravities of force, due to gravity being added. Some people could still manage this, but you would probably need to be in good shape physically to pull it off.  

Conclusion is that IF the umbrella is strong enough, this trick will actually work!

However, if you imagine a typical six-spoke umbrella, then 1000N is 166N of upward force per spoke.  It's hard to believe you could hang a 16.6kg weight off of each spoke of an umbrella without it bending.

The title text emphasizes that [[Cueball]] did indeed reach a high altitude, so we must conclude that his umbrella is some specially made high-strength device.

Since the fountain tops out at about 10m - and presumably it would be somewhat reduced with Cueball's weight on it - his feet might only be about 6 to 8 meters above the ground when he stops moving upwards.  A fall from that height is survivable - especially if the drag of the umbrella slows him down somewhat.