Washington: Washington's mayor Tuesday declared a state of emergency as Hurricane Florence bears down on the US East Coast, threatening torrential rain and flooding in the capital region.Muriel Bowser told a news conference the emergency was "effective immediately" and that the measure "ensures that we will have the resources we need to prepare for Florence."More than a million coastal residents have been ordered to leave their homes ahead of the storm's projected arrival on Thursday, with emergencies already declared in the states of North and South Carolina, Virginia and Maryland.