An aerial view of the Akamina rockslide in Waterton Lakes National Park as of June 12/Parks Canada Agency

Waterton Lakes National Park is starting to reopen areas closed by weekend rockslides, but warns that Akamina Parkway and its adjacent trails will be off-limits for an extended period of time.

“Assessing damage from rockslides is a complex process,” said Dallas Meidinger, external relations manager for the Waterton Lakes Field Unit.

On Wednesday, the Alberta park reopened Red Rock Parkway and adjacent trails and backcountry campgrounds. That move came after Parks Canada completed rock and debris removal, culvert cleaning, excess water diversion and roadway inspections.

The popular Bear's Hump trail remains closed in Waterton Lakes National Park/Parks Canada Agency

More than 50 millimetres (about two inches) of rain fell between about 9 p.m. and 11 p.m. on Sunday June 11 around Waterton townsite and Crandell Mountain causing significant rockslides.

To keep residents, park visitors and staff safe, Parks Canada quickly enacted an area closure. It needed time to determine the risk of further slides and flooding.

At least three debris fields covered Akamina Parkway along Crandell Mountain. Two of these slides are significant and will require heavy equipment to clear. Bear’s Hump trail and parking lot was also struck by a large debris slide. Red Rock Parkway was less affected, but debris still covered the road and filled culverts in several places.

An aerial view of Crandell Mountain rockslides on June 12/Parks Canada Agency

On Monday and Tuesday, Parks Canada focused on determining the extent of the damage and ensuring public safety. Five backcountry users were safely extracted by helicopter on Monday. They weren’t injured but had been caught behind the debris fields.

With initial assessments complete, Parks Canada reopened additional areas on Tuesday, leaving the closure limited to the northwest portions of the park.

On Wednesday, Parks Canada reopened Red Rock Parkway and adjacent trails and backcountry campgrounds. The Waterton townsite and surrounding areas remain open.

On June 14, Parks Canada released this map of current closures in Waterton Lakes National Park.

Parks Canada says it’s safe to travel to Waterton Lakes and explore open areas. Hikers should be extra cautious as isolated trail washouts may exist and heightened rockfall hazard is present in some areas. People should respect all signage and closures or face fines of up to $25,000 ($18,700) under the Canada National Parks Act.

“This is an evolving situation,” Meidinger said. “Parks Canada will continue to take a measured approach to reopening areas and parkways as a full understanding of impacts will take time. There is some rain in the forecast, and it is unknown how this will interact with the affected slopes and slide paths.”

He added that the slopes where the rockslides were found were affected by the 2017 Kenow Wildfire, "and it’s common to see increased erosion and runoff in areas after high severity fires in general.”

In September 2017, the Kenow Wildfire burned roughly 20,000 hectares (50,000 acres) in the park. The wildfire impacted approximately 38 per cent of the park, resulting in loss or significant damage to visitor experience and operational assets. 

Cross-border travel between Glacier National Park in Montana and Waterton Lakes is set to resume in the Goat Haunt area of Glacier. The two parks have jointly announced that pedestrian and watercraft cross-border travel between the parks will reopen on June 24 for the season. Goat Haunt is a remote area on the southern end of Upper Waterton Lake. The area is only accessible by watercraft or hiking trails.