A sinkhole of unknown extent occurs in the Colossal Cave Mtn. Park near Vail, Arizona. A new report by AZGS' Joe Cook uses geophysical and drone technologies to decipher the extent of La Posta Quemada Wash sinkhole. 22-p. report and 4 appendices online.
https://library.azgs.arizona.edu/item/AOFR-1552429219637-2
Photographer: Joseph Cook