An remarkably wet and active January so far, especially in the north
From Daniel Swain at the California Weather Blog:
A very wet and stormy period over the past month in California has brought about a dramatic reversal in fortunes in many drought-stricken regions. A series of very moist “atmospheric river” systems brought copious precipitation–in some of the typically wet mountain regions, liquid precipitation has been measured in feet. Widespread flooding of streams and smaller rivers occurred, and the Yolo Bypass on the Sacramento River has been opened for the first time in years. Numerous highway closures took place due to flooding and mudslides, and there have been several levee breaches (although so far impacts of these breaches have thus far been relatively minor).
After a couple of bouts of very warm rains, even at very high elevations, the most recent storm systems have been associated with a much colder modified Arctic airmass. The combination of cold temperatures and and an active storm track brought a tremendous amount of snowfall to virtually all mountain areas of northern and central California (at the highest mountain peaks, as much as 10-20 feet of snow!). In some places, especially along the crest of the Sierra Nevada, the last storm in this series brought extreme and crippling blizzard conditions. Parts of the Lake Tahoe region are still digging out after many feet of snow and nearly hurricane-force winds brought widespread disruptions to the power grid and transportation infrastructure.