FATMAP difficulty grade
If you want the get the couloir with powder, you have to do the Hochglück in the high winter months, Jan - March.
This requires a trip of 10k by bike and a long flat part on skis untill you reach the Eng-Alm, where the actual ascent starts.
In May the road to the Eng-Alm opens and you can go there by bus or car.
However, thats when the crowds enter the valley and there is only spring-snow left...