Just fly up Michael Moore, Rosie, Ophra, and one or two others to sit their butts on the high part until the spring thaw comes.
It looks like it was a cantilevered system where the main support was on one side of the river and the overhang went across. The counterweight was a smaller section over a smaller ravine.
From the description, the wind, picked up the cantilevered half and set it back down off the main footing.
The wind here, (east end of Lake Ontario) has been howling for several hours and the gusts are in the 60MPH range. Having some familiarity with the Nipigon area up there...Its pretty flat, the wind really gets going off the lakes and it can gust in to the 90MPH range in short bursts as it heads back onto land from the warmer water of the lake. The river valley is like a funnel and can drive the wind speed much higher. The railroaders hate the bridge next to the roadway because of the wind speeds.