The Washington Monument can be seen beyond a heavy fog clinging to the Potomac River in Washington on Wednesday. Unseasonably warm and rainy weather has created foggy conditions along the eastern American seaboard, causing many holiday travel delays. Storms and tornadoes killed at least six people and left dozens injured when they ripped through large swathes of the eastern United States on Wednesday, reports and officials said. Severe storms also hit southern and central United States, bringing heavy rain and hail. More than 100 million Americans are preparing to travel during the holiday period, with at least 91 million travelling by car, according to the American Automobile Association.