Translation:The wind violently rises to the mountain.
The adverb vehementer is derived from the third declension adjective vehemens. Third declension adjectives generally form their related adverb by adding iter to the base. In the case of adjectives such as vehemens, where the base, vehement, already ends in a t, only er is added.
I see they sometimes change recordings (and hopefully, are improving). Should we try to learn to put a stress on almost each and every word of a sentence, like this male voice is doing? If Latin speakers in the Classical period normally talked like this, I'm okay with it and will try to lean it.