One of the more far-fetched rumors is that Helene was an engineered storm to allow corporations to mine regional lithium deposits. Others accuse the administration of President Joe Biden of using federal disaster funds to help migrants in the country illegally, or suggest officials are deliberately abandoning bodies in the cleanup.

Donald Trump and others have spread claims suggesting officials are withholding assistance from Republican storm victims. And that's forcing public officials, including members of Mr. Trump's own party,