First responders transported four U.S. skiers to the regional hospital Thursday afternoon after the group was caught in an avalanche on Mt. Mackie.

UPDATED: Four American skiers injured in avalanche near Rossland

Four U.S. skiers were airlifted back to Spokane with broken bones following an avalanche near Rossland on Thursday.

Avalanche Canada is continuing to warn Kootenay Boundary adventurers that a weak snowpack poses considerable danger of slides in the back country.

According to the website’s Monday alert, conditions are primed for people triggering avalanches at the alpine and treeline level even below treeline Avalanche Canada was warning of a heightened state.

The bulletin follows the death of a U.S. skier outside of Ymir over the weekend and injuries to four Americans who were caught in an avalanche just outside of Rossland on Thursday.

The danger rating forecast remains considerable at the higher elevations, however as of Monday afternoon, it was downgraded to moderate at the treeline and below the treeline, low.

A complex and tricky snowpack exists in the Kootenay Boundary region, Avalanche Canada advises, don’t let the lure of deep powder be a draw into terrain that’s inappropriate for the conditions.

RCMP Sgt. Monty Taylor issued a media advisory on Saturday when a female skier from Alaska died after being trapped in an avalanche near Ymir.

Police reported the 32-year-old from Anchorage, Alaska, was back country skiing Saturday morning with two other people near Qua Peak, which is 20 minutes south of Nelson.

While the group was descending a slope, a large avalanche trapped all three skiers at 9 a.m. Every skier deployed inflatable avalanche bags, and two of the skiers managed to locate each other.

The third was found half buried and unresponsive. She was transported by helicopter to Nelson where she was pronounced dead.

RCMP said the group was experienced back country skiers who had proper equipment and avalanche training.

That incident followed a snowslide last week that injured four Americans skiing on Mount Mackie near Rossland.

Paula Gaul from Big Red Cats confirmed with the Trail Times on Friday that the avalanche occurred at approximately 2:30 p.m. Thursday, and resulted in broken bones to the group of skiers from Spokane, Wash.

“There was an avalanche with a group from Big Red Cats,” Gaul said. “It took quite a lot time to do the rescue, a few hours to get them out, because they were an expert group and it was a cliffy area.”

Gaul says local Search and Rescue teams were not called in as the company’s own crew was able to complete the extrication.

She says the rescue involved the Big Red Cat team skiing in through trees to the site with toboggans, securing the injured to the rescue sled, then skiing them out.

“Then you put them on a snow cat and you cat them out to the waiting ambulance,” explained Gaul.

BC Ambulance and first responders from Kootenay Boundary Regional Fire Rescue stood ground on Claim Pit Road until the downhill skiers were transported out.

“The four of them went by ambulance (to Trail),” she said. “Then they ended up going by air ambulance to Spokane, because they are from Spokane.”

Avalanche Canada noted preliminary information regarding the backcountry skier fatality on Saturday is that it occurred on a south/southeast facing aspect near 2050 metres in a cross-loaded feature.

The website also listed had a MIN (Mountain Information Network) report of a cornice-triggered Size 2 on Friday near Cabin Peak in the Bonnington range. The initial failure was in the storm slab on a southeast aspect near 2000 metres, which stepped down to trigger a weaker layer deeper in the snowpack.

Additionally, the site lists the MIN report of a skier-triggered Size 2 on Thursday in the Rossland range. The failure was a deep persistent slab on a cross-loaded west-facing slope, possibly running on mid December facets or even the November rain crust / facet combination.