Helene roared ashore in Florida as a Category 4 hurricane, trapping residents in floodwaters, peeling siding off buildings, knocking out power to millions.

Helene came ashore amid warnings from the National Hurricane Center that the enormous system could create a “nightmare” storm surge. Hurricane John once again weakened into a tropical storm Thursday evening as the slow-moving storm crept along the coast of the Mexican state of Michoacan,