is about 27 degrees to the horizontal as demonstrated by these piles of grain outside an elevator. This critical threshold describes the maximum stable slope that a dry, loose granular material can assume and is primarily a function of the grain size of the material involved. This concept is employed by geologists when assessing the stability of natural slopes.
Grain elevator near Ritzville, Washington. It’s been quite a good yield despite the dry conditions this year in the Columbia Basin.