The Big Four Ice Caves in Washington are devoid of visitors July 7, 2015. Crews were trying to recover the body of a 34-year-old woman buried when rock and ice fell at the back of the cave. The ice caves area is prone to avalanches, falling rocks and ice, and visitors are urged not to leave the trail or enter the caves. (Mark Mulligan/The Herald via AP)

By now the local parking lot snow piles have melted away, but have you ever wondered where the lowest permanent snowfield outside of Alaska is?

You will be amazed to learn that it sits lower in altitude than most of the peaks in Shenandoah National Park. Located at a mere 2,000 feet above sea level in Washington State, the huge mound of snow where the Big Four Ice Caves form is a natural wonder, and a deadly one at that.

The bizarre combination of heavy snowfall in the Cascade Range, massive avalanches that stack the snow at the base of Big Four Mountain, and lots of shade on its extremely steep north side allows the snowfield to persist through the warm summer months.

The spot is a popular destination for hikers who come to gawk at the glistening caves that form from a stream that carves out caverns as warm air melts its edges. On the busiest days, hundreds of people take the easy mile long trek, up to 50,000 people per year, making it one of the most popular trails in the Mount Baker-Snoqualmie National Forest.

In this July 2010 photo, visitors examine the Big Four Ice Caves in the Mt. Baker-Snoqualmie National Forest near Granite Falls, Wash. The Snohomish County sheriff’s office says rescuers responded to a report of a partial collapse of the ice cave July 6, 2015. (Mark Mulligan/The Herald via AP)

However, snow caves are inherently unstable and several adventure seekers have been killed over the years; the most recent accident occurred in July 2015 when tons of ice and rock fell from a collapsed ceiling. One person was killed and five were injured, one critically. The area has been closed temporarily since then.

Dramatic footage, below, shows a collapse scattering people who almost got crushed (caution: strong language).

“[The snowfield and caves] are essentially a frozen-over avalanche chute sitting over a waterfall sitting below a giant rock chute. It’s incredibly dangerous,” Shari Ireton, the spokesperson for the local sheriff’s office, explained to the Seattle Times.

The stability of the snowfield fluctuates greatly depending on precipitation and temperature. The winter of 2014-2015, prior to the July accident, saw scarce snowfall and above average temperatures.

“It didn’t get any snow at all this winter; no avalanches fell down on it, that’s the first time I’ve seen that,” Mauri Pelto, a geologist at Nichols College who monitors glaciers in the Pacific Northwest, told the Seattle Times.

As early as March, Pelto and his colleagues were certain this would be a treacherous summer at the caves.

“[I]t didn’t even get cold enough for the caves and tunnels to stop expanding in the winter,” Pelto said. “They were poised to collapse right from the start of the melt season.”

But as quickly as the snowfield can shrink, it can also swiftly grow back after a season of solid snowfall producing the necessary avalanches that feed it.

After the death in 2010 of a 10-year-old girl who was crushed by falling ice as she posed for a picture for her dad, more signage was posted at the trail head warning visitors of the hazards. But in light of the 2015 tragedy, many are wondering if that is enough.

To keep people from wandering too close, some think the trail should just be closed permanently. That decision will ultimately be in the hands of the Forest Service, which is  reevaluating its policy.