I don't think the post yesterday prevented any mishaps but I thought I'd give it a shot. After the fall on 71st. I slowed way down. There were several slick spots on my way to downtown. The one you mention on 58th was bad.
Maybe in 10 years, they can put a road condition warning sign on various bicycle boulevards similar to the ones on I5/I205 where they can warn about bicycle hazards in real time.
Work to Eat
Eat to Live
Live to Bike
Bike to Work