Why is Spring So Wet?

Usually spring is a busy time in our basement waterproofing business because of wet conditions. But why is spring so wet? The obvious answer is that snow melts and saturates the ground. While that is true, it does not tell the whole story. What about areas such as Vancouver or North Carolina where there is no real spring thaw because there is not much snow? There must be something more to it than snowfall melting.

Some say that spring rains are responsible for the soggy spring ground. However, if we look at the average annual rainfall for a given area by month, we see that spring months do not have any more rainfall on average than summer months or any other month. So why is spring so soggy?

It has to do with the evaporation rate. For every 5°C increase in temperature, the evaporation rate doubles. When it rains on a hot day, the water will evaporate in about an hour. This is why your blow drier does not just blow air - it heats it first. The reason is psychrometrics - warm air holds more moisture than cold air – a lot more. Hot air evaporates water quickly and less water makes it into the ground – and your basement.

Cold winter air does not evaporate water nearly as quickly. When it rains at 5 degrees, the water sits in puddles and soaks into the ground before it can evaporate. The ground stays damp and when it rains again, the ground takes more water still. After 3 or 4 months of this, it’s no wonder that the ground is soggy in March.

The amount of moisture in the ground depends on two factors: how much water goes into the ground and how much comes out. The evaporation rate of 1°C air temperature is far less than that of 26°C air temperature. That is why spring is so wet.

If spring has made your basement wet, we can help.