An action verb + そう often has a nuance that the action/movement occurs soon, but it also can express the distant future. Adverbs or the context would fix the meaning, as in my fist example.
See the difference.
今にも崩れそうな崖 vs 大きな地震でもあれば崩れそうな崖(In other words, the cliff wouldn't collapse unless a big earthquake occurs. This situation can't be "be about to~", right?)