3 hours to find the aircraft sounds like a very long time to me, any reason it took so long?
If the aircraft crashed in woods the trees tend to cover the wreckage and it is very hard to see even in daylight where it is. Also the low temperatures mean any wreckage or bodies will get cold very quickly and not show on a thermal camera. If the trees have leaves it is even more difficult to see as the moisture in the leaves forms a visual thermal blanket over the area.
If the weather was as bad as suggested the Police helicopter did well to launch and even get into the area. If it was the Benson machine it is an old un-stabilised T1 model. So well done to them.
FNW