A combination of torrential rain, violent flooding, and powerful wind in California has killed at least 17 people since Sunday. The storm has led to evacuation orders for tens of thousands of people, and left more than 150,000 electric customers without power. “Our message to Californians is simple: be hyper-vigilant,” California Governor Gavin Newsom said at a press conference Monday. “There are still several days of severe winter weather ahead and we need all Californians to be alert and heed the advice of emergency officials.” As of Wednesday morning, the National Weather Service had a flood advisory in place for more than 4 million people across California and a small part of southern Oregon. Read more about the flooding at the link in our bio. Photographs by Alex Welsh (@alexwelshphoto) for TIME