I think from memo the cumulo-granitus is a bit more than 25nm, so achieving Calgary 25nm MSA would be a start. Also an impossible question to answer - the runway may point at the Rockies but the route may go the other way, so presumably once you are clean - and armed with rudimentary terrain knowledge - you would be looking at heading east in that case or achieving en-route MSA if heading west before you make a dent in them thar hills. It is not much different to departing a northern Italian airport towards the Alps.