Well, now I know. It's in Ill Wind when she is stationed at Mesa Verde National Park that everything comes to a head because she's having blackouts and bugging her sister on the phone at all hours of the night, saying "Zach's dead." (Zach was her husband.) Thankfully her sister is able to convince her this is a problem that will kill her if she doesn't stop. It also helps that a heavy drinker who works construction in the park is a stupid drunk and, being the cop, it's Anna who has to pick him up all the time.
The mystery involves the death of a ranger who was a friend, and who was the stepfather of a handicapped child that Anna has become close to. Anna has two roommates while she waits for better housing, one of whom is a radical ecologist threatening bad things are happening in the Anasazi cliff dwellings at Mesa Verde because the "Old Ones" are angry at what's happening in their homes. Actually bad things are happening and it's Anna's job to figure out who and why, along with a federal agent, our old friend Frederick Stanton.
I always enjoy Nevada Barr novels greatly but this one less so than the others I've read. Can't put my finger on why because it has all the components of the best ones. Maybe it was just hating to see Anna losing control because of the bottle. Anna is so real to me that hurt. There has never been a time, though, when I wouldn't wholeheartedly recommend that if you haven't ever read Nevada Barr, you should run not walk to the library or bookstore to get in on the fun.