Possible Clues:

• US region on western edge of the Great Plains
• Check for prints and blood first on one of those likely to take flight to arid region
• Fine powder for blow manufactured in area suffering from sustained draught
• Region of severe drought in the 1930s
• Bird of the night tracks street, probing call here in central US
• Dirty postseason game?
• Result of drought, bad farming
• US region on western edge of Great Plains
• 'Grapes of Wrath' territory
• Place that's dry and clean: York, perhaps