Slope gradients are without doubt an important factor in avalanche risk management. The more important is the note that slope gradients can never be the only criteria to refer to!
The resolution of the OpenSlopeMap slope gradients base in a digital terrain model (DTM) of 10m resoultion. Outside Austria and South Tyrol the accuracy is substantially lower.
You can drag & drop as many existing gpx or kml files to the map as background information. Use the polyline tool to sketch a own route. With the edit tool you can insert or move trackpoints.