A powerful weather system is moving through southwestern United States, where 25 million people from Southern California northward to northern Idaho are under flood warnings. \nThe storm has been downgraded to a post-tropical cyclone but "the ongoing and historic amount of rainfall" could still lead to life-threatening and catastrophic flooding, according to the National Hurricane Center. \nSchools have been shuttered, flights canceled and evacuation orders for some communities have been issued, as strong winds are expected to persist across portions of the western US on Monday. \nHilary is located about 390 miles north of San Diego, in central Nevada, racing to the north at 29 mph. CNN is tracking the storm's path over the US.\nSouthern California residents already bracing for a rare summer storm were also struck by a more familiar phenomenon Sunday: a magnitude 5.1 earthquake.\nIn an area with limited connectivity? Get the latest news here.