[pct-l] North to south water shortage issue?

[Ali Mohr and Bonnie Webster]

Hey ya'll,
Myself and a friend are planning to hike from Cascade Locks to the
Cali/Mexican border this June through November. That is the plan at least...
but I was wondering what anyone could tell us about water availablility (or
lack thereof) in the desert around early fall/late summer. Pretty much, is
it possible, and what do the books not tell you about this...
Thanks so much!
Al