[mehmehshoe]

Not only storms or earthquakes...I would imagine Santa Ana winds would help this spread to the coastal regions.

[healthenclave]

Not very familiar with US geography but looks like your are correct :

(A) http://en.wikipedia.org/wiki/Santa_Ana_winds#Health%20effect...

(B) http://publichealth.lacounty.gov/acd/diseases/Cocci.pdf - Check the comments section

(C) http://dust.ess.uci.edu/ppr/pst_ZeT04.pdf