Smoke

Washington Post: Poor air quality and hazy skies as Canada wildfire smoke keeps spilling into U.S. By Ian Livingston, Matthew Cappucci, Kate Selig, Justine McDaniel, Scott Dance and Victoria Bisset

Many of Canada’s fires are over inaccessible or remote boreal land, so some are left to burn. Simply put, as long as there are fires burning, any semblance of a northerly or northwesterly wind can blow smoke toward the United States.