I recently had occasion to drive cross-country and on the trip I saw a style of building new to me. Does anyone know anything about these? Couldn’t find a great picture of one but this gives you some idea:
Looks like a road salt storage dome to me.
https://dome-corp-na.com/applications/salt-and-sand-storage/
Qadgop beat me to it. They’re fairly common in areas that get a lot of snowfall, and use road salt.
Confirming road salt storage.
Ah! And a few I saw with open doors had vehicles inside which would be the salt trucks and plows. Mystery solved, thanks!
Why are they conical, though? I’ve never figured that out.
Domes are an efficient construction technique. They aren’t too popular for general use since they don’t subdivide into rectangular rooms the way we like. But when you’re storing a giant, conical pile of salt, it makes perfect sense.
And now I know. Thank you!
It’s just a cover on a pile. basically, it’s like a gravel pile, but with a cover.
if it were a silo or something - salt can clump and not flow. Plus, a silo would require strong sides, be off the ground, need a fill chute for the trucks, etc… This way, all you need is a conveyor thingie to put the new salt up top of the pile, and a front end loader to fill the trucks (and a big door to let the loader in.) So it’s a low-strength dome that just keeps the water off.
Here’s a better picture of one (first one I ever saw):
Do I get to sound like I know/am adding something by mentioning “angle of repose”? 
I always thought they were giant beehives.