The Oroville watershed has been receiving higher amounts of rain than it has seen in decades.

The Weekly Precipitation (click here) map shows the amount of precipitation that has accumulated within the last 7 days. The precipitation imagery displays precipitation estimates in colorized contoured bands by interpreting the intensity levels of NOWrad mosaic rainfall estimates each hour. These daily summaries provide a cumulative precipitation estimate from 1200GMT yesterday to 1200 GMT (daily) or 1200 GMT 7 days ago to 1200 GMT today (weekly).

Additionally, there have been high winds throughout the country. Wind driven water is powerful water. There is little doubt high wind velocities played a part in the need for the spillway in the first place. 

Description:
The 10-Day Precipitation Departure map shows areas where precipitation is expected to be above, below, or near normal for the next 10 days.