Lightning is produced as thunderclouds produce the classic big billowy shape. These type of clouds have strong up and down drafts, mixing positive and negative electrical charges. Lightning is a result of an imbalance of electrical charges. Lightning is mother nature's way of balancing the charges out. Sometimes the lightning is between clouds or between the cloud and the ground.
Lighting is a dangerous killer.
Hundreds of people are struck killed and injured every year. If lightning and thunder are in your area take cover immediately and wait out the storm. Do not take cover under a tree, as lighting will tend to strike the highest object. Rainfall is a fact of life around the Pacific Northwest especially during the winter. But not all areas of Washington receive the same unrelenting rain.