(CNN) -- A liquid silence covers the snow-covered Colorado backcountry in February.
It swallows my words, more than once causing me to wonder whether I actually said them or just imagined them in the beauty of the surrounding moonscape.
The sound of breathing and the rhythmic "ka-chunk, ka-chunk" of backcountry skis is muted and echoless, as if heard at close range but under water.
So it is all the more disconcerting when "WHUMPH!" -- an otherworldly thunder breaks the silence, echoing strangely, as if threatening a storm on some other planet.
"What's that?" I ask -- more as fight-or-flight response, than an actual question, my heartbeat jumping 30 beats in a matter of seconds.
"That's a 'whumph,' " says our backcountry guide.
That's actually what it's called: a "whumph." Say it to any experienced winter backcountry explorer, and they will immediately know what you mean. It is the sound of a bank of snow reaching an apex of accumulation and all at once -- "settling." Add the right angle of incline and snow conditions, and you get an avalanche.
"Still scares the s*** out of me, every time I hear it," says guide Will Elliott, who has spent as much time as anyone exploring this wilderness and knows its dangers intimately. He was born and raised in the region and has been a professional guide for seven years.
"Try not to fall here," says Elliott. In these conditions, he says, it could trigger an avalanche.
I unzip my jacket and check my avalanche beacon for what must be the eighth time in an hour. The beacon is a two-way electronic safety device that straps to your chest. It works up to a distance of about 50 meters (about 164 feet) and functions both as a searching mechanism for a buried skier and as a beacon should you get buried yourself. The searcher's beacon beeps more insistently as it gets closer to the stranded skier.
As a rule, a skier trapped under the snow has about 15 minutes until he starts to run out of oxygen. The survival rate at 15 minutes is 90%. At 30 minutes, it's 50%, and at 60 minutes, it's less than 20%. Percentages decline as the amount of snow increases, according to John Snook, avalanche forecaster at the Colorado Avalanche Information Center.
Under more than 6 feet of snow, survival is very rare, says Snook, because of the crushing weight.
Six of us were backcountry skiing last week, near Leadville, Colorado, when we got word that an avalanche had killed a backcountry snowboarder near Telluride, Colorado. Using a beacon, a fellow snowboarder located the victim under 3 feet of snow, but found him unresponsive and without pulse, according to CAIC.
There was a weird silence when we first heard the news -- the guides didn't say much. We have taken all the precautions we know how to take, their silence seemed to say, but there is no way to account for everything.
On February 19, an avalanche killed three more backcountry skiers, this time near Stevens Pass in Washington state's Cascade Mountains. All 12 skiers in the group were experienced and had the appropriate equipment, including avalanche beacons. Some were swept as far as 2,000 feet down the mountain.
I have skied for most of my life -- almost always at commercial ski resorts where chairlifts drop skiers at just the right spot, obliging hosts smile warmly from every direction and a steaming mug of hot chocolate is never more than a couple of minutes away. At high-toned resorts such as Vail and Beaver Creek, Colorado, snow machines fill the gaps when snowfall is low and special grooming machines pack the snow into firm corduroyed slopes with nary a glitch to mar your path. Medical help is close by and avalanche risk is next to nothing.
Backcountry skiing is another world.
Signs of life whisper in animal tracks and evergreens, but there is the feeling that the warmth and sustenance and activity of life has gone elsewhere. There are no chairlifts or restaurants, and the beautiful, white powder that covers everything can hide treacherous obstacles such as rock piles and tree stumps. Lose a ski, miss a turn or break a leg in this environment and things can go bad very quickly.
Skiers must know the terrain, the conditions and, perhaps most importantly, their own limitations.
The danger of avalanche hums insistently in the background. It looms like the specter of death that hangs over all life, but it feels closer.
In reality you are probably more likely to die in the car on your way to the wilderness area than in an avalanche while you are skiing.
And yet there is something far more terrifying in the prospect of death by avalanche -- something primal, as if it's wired into us. It is a sober reminder that the grandeur of nature hides a frightening power and brutality.
Will Elliott and our other guide, Rochelle Ford, know about avalanches.
They know the areas to avoid and when to avoid them. They know that most avalanches happen on slopes between 30 and 45 degrees and that warm weather after a big snow can make them more likely.
But they also know that avalanche science is complicated -- that in the right conditions an avalanche can happen on an 11-degree incline. And kill you. In fact, after so many years of experience, there is only one thing they seem to know for sure: Nothing is certain in the backcountry.
In the ponderous shuffle of "skinning" up the mountain with a heavy pack, the slightest increase in effort can send you over the edge into breathlessness. Alpine touring gear allows relative comfort with a free heel and relaxed boot, and the "skins" clipped to the bottom of the skis grip the snow with incredible firmness. But at more than 11,000 feet, it pays to move slowly. The experienced move with a slow, deliberate, purpose.
If you can manage to find the right groove, a meditative focus takes over. You hear every breath and beat of your heart. You feel integrated into the beauty around you -- crystalline, hushed, elemental.
On a perfect February afternoon, Elliott leads our group in a slow zigzag up a long, snowy incline. We haven't seen another soul for several hours.
We all carry packs with various supplies of clothing, food and equipment. In addition to avalanche beacons, we each carry a giant shovel to dig out our fellow skiers should the unthinkable happen.
At the top, we rest, take a long drink and admire the incredible view. It all looks impossibly new. No one says much. Then, in no particular hurry, we remove our skins, lock down our boots and begin our descent.
We float, bouncing with a dreamy gentleness down an untouched cloud of sugary-white powder.
The sky is a perfect blue. The world is still. The mountain is ours.