Here in the US, we wouldn't use "thick" to describe a thunderstorm. We would use words such as: loud = for the sound of wind and/or lightening strong = for how much wind and/or lightening long = duration of the storm big = duration, size (how much area it covered), or strength Other words such as "wicked" or "nasty" can also be used if one wishes to be more emphatic.

I'd sooner say "heavy thunderstorm", and "loud thunder" or "a peal of thunder" for the sound.

i think loud

Loud.