Amid the relentless rain brought by an atmospheric river soaking Northern California, a flash flood warning was issued Friday afternoon for San Francisco and parts of San Mateo County where instances of flooding deemed "life-threatening" were occurring.

SAN FRANCISCO - An atmospheric river is bringing heavy rain to San Francisco on Friday, flooding roads across the city. Video shows rising waters in the Marina District and flooded sidewalks along 23rd and Dolores streets. Another video shows cars driving through flooded streets at Henry Adams and Division in the Design District near I-80.

A third day of an atmospheric river storm has inundated Northern California and the Bay Area, with the storm spreading from the North Bay south across the region, flooding creeks, roads, and low-lying areas.