The Mountain
Scholars have said that seeing a mountain in a dream carries multiple interpretations. Ascending a mountain symbolizes the dreamer's pursuit of a goal or endeavor, which could be seeking power, knowledge, or a worldly need, and the ease of the matter corresponds to the ease of ascent. Falling from a mountain indicates parting with an important person or the failure of a pursuit, and may signify falling into sins or abandoning them depending on the place of fall. The movement of mountains might forewarn of great wars or tribulations, while a mountain turning into foam or ash may not bode well for the dreamer.
Per Ibn Sirin's Muntakhab al-Kalam fi Tafsir al-Ahlam