According to Bernoulli s principle the pressure in a fluid decreases as the speed of the fluid increases.

During hurricane or tornado, the roofs of houses are destroyed completely. This happens due to Bernoulli’s principle only. The hurricane or tornado passing through the house causes a low-pressure area above the roof. But inside the house, there is high pressure. The difference in pressure is called lift. The high pressure from inside tries to compensate the low pressure outside and so this lifts the roof from inside to outside. Actually, the force inside the house is greater than the force outside which causes the roof to fly off.

The first part of the question on proof of Bernoullis principle is already given in one of the questions.