The “Foxtail Blizzard” only occurs if the timing is right; very high flood waters take so long to dry out that the wild grass has limited area to grow. If the flood subsides, but the ground retains moisture, the area becomes a field of Foxtail barley. It ripens fast and the Wyoming wind gathers the millions of dry seeds into low spots, up arroyos, and piles it up along road banks and other obstructions.
I’ve never seen this occur except in this special spot, where the geomorphology is “just right” to produce the “blizzard”. The first time I came across the phenomenon I was so confused; it was like nothing I’d ever seen. From far away it looked like egg custard had flowed across the land.