A “relentless parade of cyclones” hitting the US state of California was expected to shift farther to the north, the US National Weather Service said Thursday, as the region continued to struggle with massive floods and landslides. At least 18 people are known to have died in the recent series of storms that have lashed the western United States, bringing rainfall levels not seen in 150 years to some places. Communities have been washed out, powerlines toppled and roads blocked by rockslides as an endless deluge pounds the Golden State. On Wednesday, a swathe of northern California was under a flood watch or winter weather advisory. “The heaviest rains are expected to impact northwestern California through the next couple of days with a few inches of rain possible,” the National Weather Service warned. A later advisory said the weather system would also impact other states in the Pacific Northwest through early Saturday. That rain will come on top of weeks of downpours that have left the earth saturated, with rivers fit to burst and hillsides at risk of collapse.