Hi Sue, you need someone to look up the Washington Death Index microfilm and see if her death is listed there. Check the Sno-Isle Genealogical Society web site, www.rootsweb.ancestry.com/~wasigs/index.htm . Most Genealogy Societies will do this kind of lookup for a research fee.
However, I wonder if the death year and/or location are correct. I looked in Ancestry.com (doesn't contain all WA deaths), Washington State Digital Archives (not all records loaded yet) and Mormon Church's Washington State Death Index and didn't find her death in any of those places. Successful Searching!