SnoWhere uses Google Maps to show your search tracks on a map. If you don’t have a data connection SnoWhere can’t download the maps. You may not have a data connection in the mountains if you are abroad and you have turned off data roaming.
To make sure you can see maps, you can load the map data for the area you plan to visit in advance, either before you go on holiday or in the chalet/hotel using WiFi the night before. Just launch SnoWhere, start searching and browse around the area you plan to go to; this will load the map data into SnoWhere for use when no data connection is available.