The default style on osm.ch now includes contour lines and is updated to the latest version of the openstreetmap-carto style sheet.

(c) OpenStreetMap contributors

Elevation data created from a mash-up of SRTM and ASTER GDEM data. ASTER GDEM is a product of METI and NASA. Post processing was kindly provided by Yves Cainaud from opensnowmap.org.