(This should go in the DISC thread, mods feel free to move) The damage at the point the tornado crossed the road on Highway 3 was F1-F2 range max. This is mostly because the area we observed the tornado was the Mississippi floodplain, which is mostly flat, open fields with little for the tornado to hit. When we first saw the tornado, it was across the river in Missouri and we were unaware of the F4 damage it was doing at the time.
The houses we saw along Highway 3 in IL (in the path) had minimal damage. Tree damage was fairly widespread in the path, but not extreme (snapped trunks but no debarking or complete defoliation), hence our original F1 estimate.