Why was there a storm in San Francisco last week?
Last week, there was a storm caused by an atmospheric river. Last Tuesday, more than 200 thousand people in the Bay area lost power because of the storm. It was one of many storms that passed through California this winter.
<s>[QUESTION] Why was there a storm in San Francisco last week? [CONTEXT]  [ANSWER] Last week, there was a storm caused by an atmospheric river. Last Tuesday, more than 200 thousand people in the Bay area lost power because of the storm. It was one of many storms that passed through California this winter. </s>