In California, most of the Democratic delegates are assigned by congressional district, and a candidate has to get 15% of the vote in that district to be eligible for delegates. So I took the current voting statistics and ran a little analysis. Sanders and Biden are the only candidates who cleared the threshold in every one of the 53 districts, almost always in that order. Bloomberg hit the threshold in 21 districts, always in third place.
Warren made the threshold in 5 districts, 2 in SoCal and 3 in the Bay Area, all fiercely progressive. Rather than describe their geographies, I think I can best characterize them by naming their Congressional representatives: Pelosi. Adam Schiff. Barbara Lee. Anna Eshoo. Ted Lieu.
Sanders cleared a full 50% majority in 3 districts, all heavily Hispanic ones in the LA area.