This site has more information. It's in Norwegian, but there are some charts and graphics which give an idea how they've been trying to locate the rock by analyzing the video and checking wind speed records.
They estimate the speed of the falling rock at 280km/h (vertical) and the speed of the guy in the wingsuit at 148km/h (at 37 degr). It seems like they're still uncertain about the exact speed, though. The wind speed was about 5m/s.
One document in the video suggests the altitude that the rock passed him was 1200m... so the rock would have hit the ground 15 seconds later at 280km/h
The research website mentioned in the article is linked on that page, but it isn't up yet.
http://norskmeteornettverk.no/wordpress/?p=1329
They estimate the speed of the falling rock at 280km/h (vertical) and the speed of the guy in the wingsuit at 148km/h (at 37 degr). It seems like they're still uncertain about the exact speed, though. The wind speed was about 5m/s.
One document in the video suggests the altitude that the rock passed him was 1200m... so the rock would have hit the ground 15 seconds later at 280km/h
The research website mentioned in the article is linked on that page, but it isn't up yet.