ELI5: Why do rivers like the Skagit and Snoqualmie flood more often than others?

Imagine your bathtub. Some bathtubs fill up and overflow easily, while others don't. Rivers are like bathtubs, and floods happen when the water overflows their banks.

Skagit and Snoqualmie rivers are like bathtubs that overflow easily because of a few things:

• Rainfall: These areas get a lot of rain, especially in the fall and winter. It's like someone keeps turning the faucet on full blast! More water coming in means the bathtub fills up faster.

• Mountains: These rivers are surrounded by mountains. Mountains act like funnels, directing all the rain down into the river valleys. It's like using a cone to pour water into a bottle - it goes in much faster.

• Snowmelt: In spring, the snow that piled up on the mountains during winter starts to melt. This melting snow adds even more water to the rivers, on top of the rain! That's like adding extra water to your already full bathtub.

• Ground: The ground in these areas can get really saturated, like a sponge that's already full. When the ground is full, it can't soak up any more water, so all the extra water runs directly into the river.

• River Shape: The shape of the river and the land around it matters too. Some rivers have wide, flat areas next to them called floodplains. If a river is narrower or has steep banks, it's more likely to overflow its banks and flood than if it has a wide floodplain to spread out into.