This Intimidating 'Roll Cloud' Looks Like a Steamroller Made of Smoke

Northern Virginia commuters heading to work Monday morning were brought short by an illogical sight: a tubular-shaped cloud bearing down on them like a steamroller made of smoke:

This perverse cloud stretched from either side of the horizon and bore a resemblance to a massive tornado that was experimenting with spinning on a horizontal axis. Meteorologists at the local bureau of the National Weather Service locked onto the bizarre presence as it approached from the west and quickly loomed right above their heads; one of them snapped this panorama of it arcing over the NWS' forecasting office like a mammoth space slug from Nebulon Blooto: