After enduring one of its driest winters on record, California was being hit Friday by a frigid storm moving in from the Gulf of Alaska that triggered blizzard and avalanche warnings in the Sierra Nevada and concerns about more mudslides and flash-flooding in the southern part of the state. “It’s the biggest storm of the season,” said Jim Mathews, a meteorologist with the National Weather Service in Sacramento. “Of course, February was a dud of a month, so March is coming in like a roaring lion.”