Last I read, the effectiveness of cloud seeding is still up for debate.
Wikipedia has a section on effectiveness, “A study conducted by the National Academy of Sciences failed to find statistically significant support for the effectiveness of cloud seeding.”[1]
We've actually had a dozen mornings now in the Portland area with significant cloud cover. There's also been NW wind flow so if this technique only needed clouds and wind to push it in the direction of the fires, I don't see a reason why it couldn't work. Then again I'm no meteorologist.
Wikipedia has a section on effectiveness, “A study conducted by the National Academy of Sciences failed to find statistically significant support for the effectiveness of cloud seeding.”[1]
[1] https://en.m.wikipedia.org/wiki/Cloud_seeding