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.

The mesosphere, about 31 to 50 miles (50 to 80 kilometers) above Earth’s surface, is above the troposphere and stratosphere and beneath two other layers.