Write a short summary (two paragraphs) on Lake Oroville Dam spillover due to the precipitation related to the atmospheric rivers (ARs). For any severe weather, it is very important to first asses the weather type and them analyze impact of that particular weather.

Here, write the first paragraph discussing the weather associated to the particular incident. Mostly elaborating where it occurred, duration of the precipitation event, amount of precipitation, whether that is below/above/similar to climatological normal. As here we are talking about ARs, please also mention the AR scale. 

In the second paragraph, write about impacts of that event. How the weather type affected the specific dam and what were the consequences (life, property and infrastructure).  Any suggestions to avoid such issues in future.

Below providing a some details of that event. You all can use them as hints to start and the develop further based on the points described above. 

Hint: "Atmospheric rivers are long, narrow bands of high water vapor that transport moisture from tropical regions into the mid-latitudes.  The atmospheric rivers bring 50% or more of the annual precipitation to California and often lead to hazards, such as flooding and mudslides.  The events of January and February 2017 resulted in year-to-date precipitation totals greater than 150 – 200% above normal for many Northern California locations.

To prevent dam overtopping, the spillway was activated on February 10, 2017.  While releasing water, the spillway developed a hole almost the size of a football field that continued to expand with use. Nearly 200,000 people were evacuated as a precaution."