Thanks Tom, excellent question! Most damage (not just that pictured) were from pretty tortured urban Norway maples. by that I mean: much included bark in tight V-crotches, major structural roots cut for road and sidewalk improvements, and repeated injury from utility line clearance. This is not faulting the ROW folks, they work darn hard. As fast growing trees, these really shouldn't be near the utility lines.
Some had been already marked for removal due to obvious infection. Some that failed were sound...these were hurricane-force winds without the hurricane. I've been doing some work with the California tree failure report database. That and the related national effort seeks to find those indicators. And they are there, but hard to apply consistently and still have street trees!
No I don't have any great insights here, just thought I'd share my world. Many neighborhoods still without power. I'm fortunate to be in town, right by 3 schools, two universities, and a fire-house. So we get a lot of attention.
