For example, \(y=\frac{4}{x-2}\): Note that as the graph approaches x=2 from the left, the curve drops rapidly towards negative infinity. This is because the numerator is staying at 4, and the denominator is getting close to 0. That means that the fraction itself is getting very big and negative.
Causes of flooding. A flood occurs when a river bursts its banks and the water spills onto the floodplain. Flooding tends to be caused by heavy rain: the faster the rainwater reaches the river channel [river channel: The part of the river that holds the water. ] , the more likely it is to flood.
One cause of floods can be forecast months in advance--snow. Sometimes the ground is too hard or too wet to soak up water. The only place the rain can go is downstream. Usually rainfall of more than one inch in one hour is needed to cause a flash flood. Sometimes a place can get hit by a flash flood even if it's sunny because it might be raining on higher ground somewhere. The floods in Poland this summer weren't flash floods. They were caused by heavy rainfall but the rain was spread out over days. So much rain fell that the rivers couldn't handle all the water.