It's a "transient luminous event" or TLE that happens above the clouds, in the mesosphere, when there is intense electrical ...

Early Tuesday morning, a delicate, wispy cloud type rarely seen formed over western Montana, lighting up the pre-dawn sky.

When the Hunga Tonga-Hunga Ha’apai volcano erupted underwater in January, it created a plume of ash and water that broke through the third layer of Earth’s atmosphere.