british_columbia canada located inside national park sub range construction near terminus building hotel nearby prominent tourist destination canadian west easily accessible road railway studied glaciers north_america retreat years extensively documented physical characteristics located south mount sir west rogers pass british_columbia outflow forms feeds glaciers accumulation area square kilometres area square kilometres total size square kilometres estimated mean depth metres highest point measured metres exposed bedrock terminus shows effects glacial history nations people present valleys east west evidence settlement area found european visit major rogers railway surveyor examined area search viable pass completion nearby rogers pass surrounding area western canada tourist destinations established small hotel built near north end year hotel expanded described visited americas point called great promoters word big water referred river applied gradually replaced great adopted 1960s new influx visitors brought recorded ascent likely climbed earlier built near house use swiss guides hired accompany visitors nearby peaks family family pennsylvania family visited subsequent trip noticed visible retreat terminus children william george mary later amateur photographers began study pictures taken fixed points william presented findings study methods considered breakthrough new field continue visit area summer death level family carefully photographed surrounding area glass plates transported mountain sent philadelphia later modern medium format cameras continuing photographic evidence support scientific measurements grandson alpine photographer noted static nature alpine area related short growing seasons major differences contemporary times early 1900s retreat presence saw trees observed grandfather perspective little difference glaciers kilometres man things constructed bypassed site numbers visitors declined hotel closed demolished thirty year period previously popular new completed route closely followed original line joined major transportation route began improve facilities opened new trails constructed giving access located significantly farther away half century saw studies retreat pronounced studies sparse compared studies european glaciers studies detailed north american standards scientific study performed family george william including measured glacial retreat annual photos fixed points period world war great depression saw fewer observations closing drastically reduced number visitors area federal started assessing measurements bureau conducted yearly studies years measurements taken began surveying study examines rock order determine glacial retreat begun satellite imagery measure size retreat scientific research began late 1800s retreating shorter periods small advances terminus retreated research indicates period advancement terminus advancing total net retreat period lost mass regained maybe
Illecillewaet Glacier