It is often said that the turbulence can be extreme enough inside a cumulonimbus to tear an aircraft into pieces. ... Thus, cumulonimbus are known to be extremely dangerous to air traffic, and it is recommended to avoid them as much as possible.

What happens if a plane goes through a cloud?

When an aircraft moves through clouds containing water vapor of a certain temperature, the sudden cooling caused by the passing of the aircraft, spurs the vapor to freeze into ice crystals, which then fall through lower clouds.

Can planes fly through supercells?

"Whereas here, you get supercells that planes can't fly through, planes shouldn't fly through, because there's hail and graupel and all types of things that can damage this plane." ... "Its role is to fly ahead of the storm in the inflow collecting radar data."