Ignorosphere not!
Polar mesospheric clouds exist at high altitudes and are common at the Earth's polar caps.
They also are known as noctilucent clouds because they gleam in the night sky. See this story for more on the clouds.
In June 1999, there were sightings of huge noctilucent clouds over Colorado and Utah, at about 40 degrees north. Since then, sightings also have been reported in Montana.
The clouds may well have appeared over locations, but there are no officially recorded sightings. Do you think you have seen them? Tell about the sighting here.