Johnston Canyon’s popular waterfalls are temporarily inaccessible by the main trail as rock slope remediation work gets underway in Banff National Park. CochraneNow/Lauren Meister .captiontext { font-size:90%;font-style: italic;margin-right:20px; } Visitors to Banff National Park will need to find an alternate route to Johnston Canyon’s popular waterfalls as rock slope remediation work gets underway. Parks Canada says the closure is now in effec…