In the winter of 1981-82 the Sacramento Valley flooded, with water levels rising to the second floor of buildings along the Sacramento River. After the flood city officials raised structures at least one floor. Part of the problem was warm rain melting earlier snow packs, flooding the valley.
We are about to experience a similar event this weekend. With four to six feet of snow on the ground, torrential rains are forecast to 8,500 feet in the Sierra, resulting in a flood warming. Sierra rain is forecast to be 10-15 inches this weekend. Streams will rise to flood levels through the Sierra as the warm rain melts the snow pack.
Flooding may not rise to the degree of the 1882-83 of flooding, as the atmospheric rivers of moisture the Pineapple Express may not be as intense as in 1862-63 and modern flood control systems will moderate the flood waters some, but they could be overwhelmed. Stay tuned; flooding is on the horizon.
[Edited to correct dates]