I have a book called Pasajes Literatura by Bretz, Dvorak, Kirschner, & Kihyet. In it there is a passage from La conciencia by Ana María Matute. There is a part that says, "En efecto, allá afuera, Mariana oyó el redoble de la lluvia contra los maderos de la puerta. Una lluvia sorda, gruesa, anuncio de la tormenta próxima." I know sorda means 'deaf,' and I saw that the book gives a footnote translating the word as 'deafening'. Deafening in English means 'very loud' like loud to the point that it makes you go deaf. Is this a valid translation of the word sorda because when I look it up in the DLE of the Real Academia Española, I don't see a definition resembling something like 'really loud.' In fact, all of the definitions appear to me to mean 'really quiet.' Is 'deafening' a mistranslation or a valid translation? I know gruesa would mean something like 'heavy,' so maybe the combination of sorda with gruesa is what makes it deafening?
Link to the DLE: https://dle.rae.es/sordo?m=form
"callado, silencioso y sin ruido." "que suena poco o sin timbre claro."