It’s a rare and unusual phenomenon, but ongoing wildfires in Nova Scotia have some radio listeners in the Northeast picking up stations they’ve never gotten before. Smoke in the atmosphere is causing radio waves to bounce back to the ground instead of traveling into space. Combined with a pattern of warmer air trapped above cooler air, radio waves can bounce over long distances instead of dissipating.
While typically not replacing local stations, empty frequencies can be filled. Reported incidents include Long Islanders being able to pick up signals from Philadelphia and Richmond, Virginia. Another report is that the DC area has found stations on the dial from Tampa, New Orleans, and Kansas.
Well, the first phenomena is called tropospheric ducting and it’s actually pretty common in that region. This is caused by a temperature inversion at low levels of the atmosphere (in simplest terms) and results in VHF/FM signals being reflected off of the temperature boundary – extending their range significantly. This can last for many hours and during the summer months can be a daily occurrence in some parts of the country. Getting signals from Virginia to bounce into NJ or Long Island is not that unusual.
And the second (seemingly magical) phenomena is called e-skip, which is caused by signals in the VHF part of the band bouncing off of the e-layer of the ionosphere (which most active around summer solstice). Less common that tropospheric ducting, but not rare either in late May/June/early July. It tends to be a more fleeting occurrence and you really have to have some luck in catching/IDing signals when e-skip is occurring because the signals fade in and out, even on the same frequency.
Neither of these things have anything to do with wildfire smoke and neither is all that unusual given the time of the year, so whoever wrote this article just flunked their first electrical engineering quiz.