What does 2 inches of rain mean?

Answer 1

First, practically, 2 inches of rain is quite a lot of rain and generally means you can expect some flooding. The measurement is made by measuring how much rain has fallen over a given area in a given amount of time. Since rain falls more or less uniformly over a given surface, you can measure the average rainfall per unit area by simply capturing the rain that falls on that area. You can do this quite easily at home. Just use any container with a uniform circumference and put it in a place outside where it won't blow over and won't receive extra water from splashes and such. After the storm, use a ruler to measure how deep the water is.