What Does "shadows" refer to?

Question

Turning toward our house on the hillside, I see movements of a different kind, tall shadows stiffly pushing through the currents.

I think it refers to her brothers, mother and father. But I'm not sure. Could you explain it to me please?

The fuller text is here:

The hill is paved with wild wheat. If the conifers and sagebrush are soloists, the wheat field is a corps de ballet, each stem following all the rest in bursts of movement, a million ballerinas bending, one after the other, as great gales dent their golden heads. The shape of that dent lasts only a moment, and is as close as anyone gets to seeing wind. Turning toward our house on the hillside, I see movements of a different kind, tall shadows stiffly pushing through the currents. My brothers are awake, testing the weather. I imagine my mother at the stove, hovering over bran pancakes. I picture my father hunched by the back door, lacing his steel-toed boots and threading his callused hands into welding gloves. On the highway below, the school bus rolls past without stopping.

Educated by Tara Westover

Answer 1

We know from the description of the trees and the wheat that it is a windy day.

The sentence following your bolded query, mentions the brothers who are "testing the weather" (a previous question).

The tall shadows in the bolded sentence refers to those brothers.

The currents they are pushing through means the wind – since they are "testing the weather".

They do this stiffly perhaps because they are braced against the force of the wind, and the sentence is perhaps written like that to create a contrast with the swaying trees and rippling wheat.