Could be a dust devil.

I think the reality is that no one knows but there are a lot of more or less intelligent guesses.

I think "seeps" might have been a descriptive word, as "flow" can imply erosion.

What the lady is suggesting, a "seep" which dissipates into the air and back into the ground, is fairly common with liquid water in hills in the western US. Especially in later summer, as the water supply diminishes.

Trying to make definitive statements while peering into the Foggy Mirror of the God of Lack of Knowledge sure looks risky.

Is that dust that's fogging up the mirror? Condensation? Dirty, gooey condensation? Maybe CO2 liquifying and scooting down the hill a ways before evaporating?

Or bugs? They could "bloom", or proliferate at various times before heading back into quiescence. Sort of like roses in the Spring, or maples in the Fall.

Don't know. And it's clear that someday it will be known. Too bad the bucks which could buy the knowledge are being spent elsewhere.

Arf