Hi Garry,
It is very common up in the Moses Coulee area of WA, I have lots of collections and a list of the plots where we found it in 2013-2014. Unfortunately I can't easily find the plot locations but probably could if you really need to know.
Heather Root also found it in central OR in 2012.
I'd say it is common in both states in the correct soil crusty sort of place.