Hintertux
Austria's only year round glacier, with reliable snow long after the valleys have closed.
Hintertux tops the list because it never closes. The Hintertux Glacier is the only ski area in Austria open every day of the year, rising high enough to hold firm, dependable snow deep into spring and through the summer, so a late April or May trip here is a sure thing.
The terrain is high and snow sure rather than charming, and you ski the glacier itself rather than tree lined valley runs, but for guaranteed late season snow there is no rival in the country. The clear number one for spring.