I'd imagine it has to do with low humidity, winds coming off the peaks/lakes to the east, and the relatively high elevation (3,000'). Looks like the Andes crest down there is only about 4,000'.
It’s just absurd the way they acted like these people were violent drug dealers or something. Like yeah rabies is a real concern, but that was absolutely the wrong way to go about the situation. I can never understand why police departments have such disproportionate responses at the weirdest times and other times hardly do anything at all.