Just a tip, ask the highway maintenance guys, (I think its Volker Stevin) in your area. When i use to work on the highways, the longer into the year it got it was in the Provincial contract that there was to be roadchecks done everynight to check for snow and ice buildup on remote portions of the secondary roads. I tell you what, That is when ya see the big ones. Maybe the guys there will share there sightings with you. Just a suggestion.
Goodluck!