Chair steepness? It's the pitch of the portions of the runs you ski that matter. KT rules!
A friend from Big Bear was skiing with me at Squaw. His fancy GPS goggles showed that Granite Chief matched the statistics for Silver Chair at Big Bear almost exactly. Silver is a run I can cruise directly. Granite works me. But every way down Silver is groomed to perfection (if you like groomers). Granite was all bumped out. We calculated that it took 10 times as many turns to get down Granite than Silver (engineers are weird). Lift steepness is not the defining measure.
Regardless, it is an entertaining measurement. I have no statistics but an hour or two on Olympic Lady at Squaw Valley finishes my thighs. It's not long but serves very steep terrain. Maybe it won't make the list because of the few hundred foot flat runout at the bottom but aside from that the lift really elevates. And once you are up, you must come down at almost the same pitch. Olympic Lady is my favorite chair!
Scott at Alpine is pretty steep too. But there are easy ways down that chair. And the (short) flat runout is a pain - maybe that hurts it's ranking. Under the chair is a steep challenging run though.
Gunbarrel at Heavenly?
Geronimo at Big Bear?
The tram at Snowbird opens up the most uninterrupted steep terrain I have skied.
Where do you find this info? Do I have to invite my buddy and his fancy goggles to ride those chairs?