Well, what I do is look at the newest events in Oregon, and the events are up at the top. But I am looking for something that will notify me my email. I setup a notification yesterday of all events 300 miles away from me, and I am sure to get Washington, California, and Idaho events.
You can set your search radius to include the whole state but then filter the results to only include ones from oregon in the "within" section. That should do what you want it to.