I think Gyrfoam is right, but to add to it, wings and flaps can accumulate ice that a pilot cannot see,and do so quickly, as the weather up here in CNY was changing on a front of about 50 degrees to 30 degrees on the ground and probably more dramatic at 2500 feet. Conditons on the ground even driving were shitty.
So, if their wings were designed for a minimal speed aloft of say 120 knots for landing and they had lets say 160 knots then the landing gear going down slowed them down to a perceived 120 knot level, and with the increasing ice on the wings, to an airspeed way below that acutally, it was a pitch and roll. The mass was too heavy for the forward motion to sustain it above the pull of gravity. It seemed the landing gear was the slow down that with included with the weight of ice, was not calculated in the airspeed,or could not be,based on how fast the freezing rain was falling.
It was sad. That airport should have been shut down. Many prior landings reported significant "rind", and it was a windy night.