From a glacier measurement tour with my brother to Hagafellsjökull Vestari last autumn - Hagafellsjökull is one of the outlet glaciers from the ice cap Langjökull. A smooth whaleback newly appearing from the retreating glacier. Note the fracture on top of it and imagine how the distal part (distal from the glacier) of the whaleback will most likely be eroded away in the next adwance of the glacier or in the next glacial period. After that we will most likely have very steep lee side of the whaleback and that would be called roche moutonnée.
This development of a whaleback into a roche moutonnée doesn't fit completely what has been written about the necessity of cavities and low pressure on the lee side of the bedrock. I can't see why the low pressure is needed to make the steep lee side end after the fracture has been made there.
This whaleback is also remarkably similar to the famous Kirkjugólf (church floor) in Kirkjubæjarklaustur in Sout-East Iceland, south of Vatnajökull glacier. Here you can see a photo of that place from 2011 when I was there with other geology students in a study trip for first year students in general geology.