Quoting an article in FactCheck.org by Catalina Jaramillo: "The relentless storms that hit California from Dec. 27 to Jan. 16 caused extreme flooding and extensive damage in most of the state, killing at least 22 people. A series of storms hit back to back, soaking the state in the midst of California’s driest three-year period on record."
“Given that global warming is increasing the amount of water vapor, it does seem reasonable to suggest that climate change may be making these storms stronger,” Travis A. O’Brien, assistant professor of earth and atmospheric sciences at Indiana University, Bloomington, told us in an email.
“Indeed, climate model studies of atmospheric rivers and global warming … suggest that atmospheric rivers become ‘stronger’ (more water vapor transport) in a warmer climate and are generally associated with higher precipitation amounts,” O’Brien added.