| Flattnitzer See Hemmasee | |
| Location: | Flattnitz Pass |
| Coords: | 46.9381°N 14.0383°W |
| Catchment: | 0.57km2[1] |
| Area: | 0.0196km2 |
| Max-Depth: | 2.8m (09.2feet) |
| Volume: | 27000m2[2] |
| Pushpin Map: | Austria |
| Pushpin Map Alt: | Location in Austria |
| Elevation: | 1370m (4,500feet) |
Flattnitzer See, also known as Hemmasee, is a lake near Flattnitz Pass in the Gurktal Alps. It rests in the municipality of Glödnitz, in Carinthia, Austria.