What is this phenomena? ?

It could be a water pipeline that broke. It can't be only sand, there is no dust. If the colour comes from the sand, then it is a mixture of sand and water.

Usually one think of sand as something without dust because we see it mostly on beaches where the water washes the sand and keeps the dust as sediment. But if you ever drive in the desert, as I did in south Morocco, it is full of dust ... coming everywhere in your car.

Anyway, impressive video. I see people watching the outburst from relatively close so I guess it is not something too threatening. I think it is a broken water pipeline.

my best guess is that an underground cavern collapsed and the air trapped inside forced the sand to rush out.

I dont what is that phenomena . But it is scary and terrible