Which skiing mountains are low altitude?

The Uppsala Alpine Center in Uppsala, Sweden is a good candidate but I don't know if it is the lowest.

It is between the 0 and 5 m height lines on the map. I don't have exact data but I would guess it's somewhere around 3, perhaps 4 meters above sea level.

There are also two resorts in Stockholm, Sweden, in Saltsj�¶baden and Liding�¶ which are both situated by the sea between the 0 and 10 meter height lines.

Kvisthamrabacken in Norrtälje, Sweden is 0,9 m above sea level and is probably lower then the "resorts" mentioned above.

These are not really ski resorts but rather a hill with a lift and no accomodation.