For Robert Friend, home was a tent pitched down by the American River off 12th Street. It was quiet, secluded in the bushes, a respite from life on the pavement downtown.

Or at least it was until the storms came.

“I got flooded out,” said Mr. Friend, 48, looking weary on a recent afternoon as he stood on the sidewalk he had escaped to a few blocks from the river. “This is the worst winter I’ve known in the 10 years I’ve been here. Last night and the night before I was just under a tarp, waiting it out. It was freezing-raining all night long.”

The rains that lashed California this year, continuing with yet another wave of downpours through last weekend, have pulled this state out of a historic drought. But they also exposed the extent and agony of homeless women and men who have long made homes along the banks of the now-swollen rivers across California, and particularly in Sacramento, a city of 480,000 where a largely hidden community has lived on the outskirts since the Great Depression. According to city and state officials, about 2,700 of the 118,000 homeless people in California live here.