A few years ago, Fila ran a magazine ad with three-time Queen of the Hill Julie Zell pointing it down some ultra-steep face in Alaska. She was surrounded by the sea of her slough (pronounced “sluff”), a massive waterfall of snow careening down behind her that spanned the entire photo. What made the image so spectacular was the sense that she had somehow managed to escape impending doom, her daring speed evident even in the still photo. The tagline, printed in bold black letters across the bottom, read, “You go, girl.”

Dozens of images like these have popped up in videos and magazines in recent years, depicting pros playing a dangerous game against forces where losing isn’t an option. Some of the most spectacular shots have come from these slough-getaways, snow chasing the rider down the mountain like something out of a James Bond movie. The idea of flirting with sloughing terrain-avoiding it, intentionally riding with it, or trying to outrun it-has put snowboarding on the same level as surfing big waves.

It’s an undertaking which, while it does make for some pretty dramatic action, requires tremendous skill and understanding of snow conditions. Particularly in Alaska (which has often been referred to as “the North Shore of snowboarding”), where steep, exposed terrain is consistently accessible, and snowboarders are pushing the envelope of what can be ridden. And much like the years of experience it takes to gain an understanding of the sea, riders who venture into this arena must have a highly developed sense of the ever-changing, volatile conditions of the backcountry.

First, it’s important to recognize that there is a big difference between the sloughs that you see in most of these images, and avalanches. “Technically, sloughs and avalanches are totally different things,” says Alaska heli-guide Dan Caruso. “An avalanche is a slab that breaks off like a big plate-if something like that goes, there’s not a chance you’re going to be able to get away from it because the whole slope is sliding from under you. A slough is a point release where only the surface releases and goes down the fall line, so it’s possible to avoid it.”

Sloughing faces are pretty much par for the course in Alaska, but Caruso says it wasn’t until fairly recently that riders started experimenting by actually riding along with them: “It used to be that you knew they were coming and did everything you could to avoid them. Nowadays people are outrunning them.”

Despite her Queen of the Hill status, Zell is an advocate of avoiding sloughs (or at least trying to) no matter what. “Even if you have experience and gain a feel for being able to predict which direction the slough is going to take, you don’t know how fast or dense it’s going to be. You don’t want to get sucked in because it can put you in a precarious situation. It’s not a matter of getting buried, but where the slough would take you if you got caught in it.” Zell points out that whatever snow is released is going to move directly down the fall line-over cliffs or whatever other obstacles are in its path-places you’d rather ride around, not over.

Zell says that she analyzes what to do if she were to get caught in a slough the same way she looks for what to do in case of an avalanche. “I study the features that are in my path, like cliffs or bergstrum gaps. You have to study and memorize the runout, or where you’ll end up if you’re taken out.” On an open face where rocks, cliff bands, and gullies aren’t an issue, slough can be avoided by working your way across the slope and down, rather than riding directly down the fall line. This way the slough will pass by, keeping you out of harm’s way, says Zell.

Terrain traps, or places the snow gets sucked into (like gullies) should be avoided. Zell looks for islands of safety in case anything goes wrong in advance, but admits that sometimes you just have to be prepared for the worst. “You’ll see me making a pretty bad judgment call in this year”s video Uprising, Teton Gravity Research. You really have to pay attention to what’s behind you, and I didn’t do that. I turned right in front of my slough so that it caught up to me. Luckily I was going fast enough and had good snow below me, so I was able to outrun it.”

Fortunately Zell spent the good part of the last two seasons riding a race board, in addition to her global repertoire of big-mountain descents, and is able to get that impressive shot off without paying too high a price. It’s also what has allowed her to return to Alaska year after year unharmed, despite some of the trauma she’s seen in big-mountain settings, including the death of former Killer Loop teammate Neil Edgeworth during a photo shoot in Chamonix in 1997. “If you’re going fast enough and the snow below you is good, outrunning your slough is not even an issue,” she says. “But I wouldn’t recommend it.”