AFP, WASHINGTON The US on Saturday celebrated its 250th birthday with parades, flyovers and fireworks to come, as US President Donald Trump stamped his mark on the landmark anniversary in a deeply divided nation. However, weather threatened to spoil Trump’s super-sized party in Washington, as tens of thousands who had gathered on the National Mall hours ahead of a campaign rally-style address by the president were ordered to evacuate due to an approaching thunderstorm that followed hours of searing heat. While many streamed toward exits, chaos broke out as others refused to leave or tried to surge back in, shouting: “charge,” and “Trump, Trump.” US presidential impersonators pose for a photograph at Mount Rushmore in South Dakota on Friday. Photo: Bloomberg “We are evacuating. Move,” offic