For more stories like this, check out The Chronicle’s weekly Travel newsletter! Sign up here.A burst of late-season storms rolling across Northern California is filling in the region’s mountains with snow at a time when many people had chalked up this winter as another disappointing drought year. After a three-month dry spell of paltry precipitation, the La Niña weather pattern in the Pacific has unleashed a barrage of wet weather this month that could continue, on and off, through early May. It’s been an erratic winter in the mountains.