Tag Archives: Avalanche Control

Avalanche Control in Yellowstone Park?


The National Park Service uses artillery shells to mitigate avalanches on Sylvan Pass, which allows access to the park from the east. In the winter, the pass is open only to snowmobiles and


photo courtesy of newwest.net

other “over-the-snow” vehicles. A decade ago, a few thousand snowmobiles might make the trek from Cody to Yellowstone Park over Sylvan Pass. Now the number is closer to a few hundred. Ever since the use of two-stroke snowmobiles was banned in the Park, many of those users are going elsewhere. And yet still the Park clears the slidepaths with explosives.

The annual cost to mitigate the avalanche hazard in the 20 slidepaths on Sylvan Pass, which often gets 350 inches of snow annually, can be as high as $325,000, according to Billings Gazette. Avalanche control teams use a 105 Howitzer, creating  avalanches when the road is closed. Teams have also

Avalanche Paths on Sylvan Pass, photo courtesy of National Park Service

Avalanche Paths on Sylvan Pass, photo courtesy of National Park Service


105 Howitzer used at Alta

dropped explosives from helicopters when the conditions are too dangerous to access the Howitzer.

Sylvan Pass is the only avalanche area within a National Park that utilizes explosives to stay open for tourists. With a high cost and low use, it seems an impractical use of funds.

In 2007, when the Park considered closing the pass in winter, local snowmobilers and politicians were outraged. Conservation groups tried to push back, claiming, among other things, that the risk of unexploded shells tipped the risk/reward calculus into the red. In 1997, a tourist brought an unexploded shell into the visitor center, no doubt starting a massive panic.

According to some estimates, as many as 300 unexploded bombs could be hanging around in the Sylvan Pass area. That number seems both high and astonishing. If there are only half that many unexploded shells, the risk is still high. Some war zones probably aren’t that crowded with duds.

Explosives can fail to detonate for any number of reasons. Once an explosive is lit, it is considered live until it detonates. In military parlance, duds are known as “unexploded ordnance”, and they can pose a risk of detonation even decades after they are lit. A dud, then, is not something to mess around with.


Plows clearing roads in Yellowstone

Recently these duds have been in the news, since the numbers have recently been released. In my opinion, the real issue isn’t the duds, but the need for explosive control at all. Does this road really need to stay open for what seems like an average of one snowmobile a day or less?

Defenders of snowmobiling in Yellowstone continue to fight their battle, hanging onto what Clinton nearly succeeded in ending. But at what cost? Should we continue to keep Sylvan Pass open with federal dollars? Should Yellowstone allow snowmobiling, even the kinder gentler four-stroke engines?

Snowmobiling allows widespread winter access to Yellowstone. And perhaps, that’s a good thing. But with unexploded artillery shells and an explosives budget as high as any Class A ski area, I’m not so sure the cost is worth the effort.

I’d love to hear what you think. Leave your comments below.

Bombs Away


It started snowing a few weeks ago at Crystal Mountain, and it hasn’t stopped. In just a matter of days, we went from diligently making snow in the base area to cover over thee remaining brown spots to searching for more places to plow the snow. Currently our snow pack is at 150% of normal. We just hit 100″ on the ground in Green Valley–an earmark we usually don’t see until February.


The helicopter is loaded with explosives

With all the new snow, and the recent avalanche hazard, we brought in a helicopter on Friday to assist with explosive control. Helicopters, like the Ranger we used on Friday, allow us to drop big explosives onto the slopes, creating avalanches without putting ski patrollers on the dangerous slopes.

Yet helicopters are not part of our normal routine. Wind, weather, radio communication and airspace control add new dimensions to an already complicated plan. Thanks to Snow Safety Director, Chet Mowbray, and Patrol Director, Paul Baugher, who orchestrated the heli missions, we were able to test our slopes and find the weaknesses in the snow pack, especially in Southback.

We dropped 50 lb. bags of explosive onto the chutes on the SE left side of the King in Silver Basin, and got impressive results. Throughout both basins as well as Northway, the slopes were bombed into submission, either releasing big slides or proving their strength. Overall, the helicopter mission was a great success. We were able to open both terrain pods this weekend. Unfortunately, High Campbell chair went on wind hold not long after Southback opened. However, it should be open today, offering up some very good skiing to those willing to hike for it.

Unfortunately we had a very close call during the heli mission in the Niagras and Employee Housing areas. Employee Housing is the new slide path created a few years ago, and it is roped off with the rest of Niagras. You must enter Employee Housing first through Gate 7 then through Gate 8 and drop in from the top. However, poachers have been consistently ducking the rope from the Left Angle Trees area. We have caught many of these violators, who have lost their skiing privileges. These poachers could also pay a hefty fine.

But one hapless poacher almost lost more than his season pass on Friday. He almost lost his life.  A ski patroller had positioned himself along the rope line to make sure no one ducked the rope while the helicopter dropped it’s payload on the slope. (As an aside, let me just state that this use of personnel is not only a waste due to the actions of non-law abiding patrons, but also a contributing factor to why Northway doesn’t get open earlier. If we have to expend a patroller to prevent and chase after poachers, that’s one less team working on an avalanche route.)

The helicopter had just dropped a 50lb. shot onto the middle of Employee Housing when a poacher ducked the rope. The ski patroller positioned along the rope line yelled at him, “Fire in the hole! Avalanche control in progress! Fire in the hole!” The skier, dressed in all black, looked up at the patroller and stopped. Then he did a very stupid thing. He dug his poles into the snow and pushed off into the open slope. The ski patroller kept yelling until his voice was hoarse. He made a radio transmission informing the blasting team of the poacher. There was nothing anyone could do but watch. The 90-second fuse had been lit and now, in less than a minute, the slope would explode.

The poacher continued out, oblivious to the danger. From the parking lot, Chet and Paul watched with their hearts in their throats. The entire patrol, listening on the radio, held their breath. The poacher skied on, making wide, slow, agonizing turns. The patrol teams watched him get closer to the bomb. The fuse was running down. It would blow in twenty seconds.

Then the poacher skied right over it.

From the parking lot, onlookers screamed in vain. “Keep moving! Don’t stop! Get out of there!”

The poacher couldn’t hear them. He continued on blindly.

If the slope broke out in an avalanche, he would surely be caught. He was still close enough to be blown to pieces. A few more seconds passed.

Then boom.

From above, the ski patroller on the rope line watched. It took a moment for the smoke from the blast to clear before he had a good view of the slope.

Employee Housing did not avalanche. The poacher did not get caught. He was very, very lucky. I, for one, can only hope that this close brush with oblivion scared him straight.

In spite of the actions of this one violator, the helicopter mission was a success. I was able to fly over the slopes and utter the fabulously thrilling words “bombs away” into the mic. Only through a coordinated effort (and considerable luck for our one violator) was this possible.

We still have more snow in the forecast in the next few days before a possible break in the weather comes later in the week. For those once-a-year skiers trying out their new Christmas presents, Thursday and Friday could be clear and cold, offering great skiing and good visibility. See you on the slopes.

Deep Snow, Avalanches and Keeping Your Brain Screwed on Straight


Avalanche Prone Area

The Cascade Mountains are in the midst of a major snow cycle. Pacific storms bringing wind and significant snowfall have pounded the Pacific Northwest mountains the past two weeks. As of yesterday, Crystal Mountain had received 40″ of snow in the past two days, and another 18-24″ is expected today. Another foot or two is on deck to Thursday.

Yesterday we posted signs at the ticket windows and the base of all chairs warning people of the hazards of deep snow. We recommend skiing with a partner and keeping them in sight at all times. We also recommend wearing a transceiver and carrying shovel and probe while in avalanche prone areas. Those areas at Crystal are specifically marked. Northway, Southback and Bear Pits are accessed through gates marked “Avalanche Prone Area”. And yet I’m surprised by how many people yesterday in Northway were not wearing transceivers yesterday.

Northway opened at 2pm yesterday after a full day of avalanche control. Moments before the gates opened, the lift went down for a mechanical reason. Eager powder hounds were amassing at the gates.


The Hike to Morning Glory looking back at Northway Notch yesterday

Ski patrol wanted to open the terrain in order to get tracks in there. Skier compaction is the best way to manage avalanche hazard. Ski and snowboard tracks today will keep the hazard lower tomorrow as new snow creates subsequent layers.

We decided to open “Short North”, asking people to return on I-5 rather than dropping down to the bottom. On a very small but steep section of the horizontal return trail a small pocket of snow pulled out and buried a skier.


It was easy to get “gold fever” yesterday. Photo by Andrew Longstreth.

She was not wearing a transceiver. The snow carried her about thirty feet to a tree island where subsequent snow buried her. She was not tumbled or pushed very far. Luckily, she was able to punch one arm out of the debris and remove some of the snow near her airway and was therefore able to breath. After approximately 10 minutes, ski patrollers arrived. Witnesses at the scene had already probed her, and she dug her out. She was okay, and able to return to the base area under her own power.

We can all learn many lessons from this close call.

  • Wear a transceiver and know how to use it. Even when you aren’t planning on riding in an Avalanche Prone Area, wear it anyway. You just might be tempted to drop in when we open the gates.
  • Ski with a partner. Keep this partner in sight the entire run. Plan your run ahead of time. Decide where you will stop and wait for the rest of your party. Make sure everyone is accounted for before continuing on.
  • Ski one at a time. Do not drop onto a steep, deep slope with twenty other skiers and riders. Do not drop in above someone else. I know this seems like an impossible task. Often when we drop the gates everyone bum rushes the slope all at once even when we’ve warned them not to. Talk to the other people standing there and stake your lines beforehand.
  • Carry a cellphone and put the ski patrol on speed dial. The emergency-only number is 360-663-3064. Witnesses at yesterday’s close call claim that it took a full five minutes before anyone called patrol.
  • Carry a shovel and probe. Know how to quickly deploy them. Practice using them (and your beacon) at the Easy Searcher search park located next to the Campbell Basin Lodge.

It’s easy to get “gold fever” when standing at the top of a bottomless, untracked slope just as the sun peaks out. You feel like a hero. You feel lucky and blessed. And you are. Just remember to keep your brain screwed on straight. The best skiers and riders always do.

I Love the Sound of Avi Bombs in the Morning


Avalanche Control


Photo by Andrew Longstreth

Powder hounds love the sound of avalanche bombs in the morning. To wake to the boom and rattle of windows, to feel the deep compression reverberate across the valley, to open your eyes to the alarm clock of explosives means only one thing. Powder day.

But how do we ski patrollers decide when to go out for avalanche control? Some days the rumble of explosives promises fresh powder, and other days the hillsides are quiet only to reveal deeper and lighter snow than before. So what gives? Why do we go out some days with 3″ of new and not others with 8″?

There are no hard and fast rules. This is weather we are talking about, after all. Our avalanche forecasters decide how the current weather will affect the snowpack, and make the decision to wake us all up at 4AM to come in for avalanche control. Also known as “Avi” or “AC”, we mitigate the avalanche hazard by using explosives or ski cutting to create avalanches while the slopes are closed, so that they don’t happen later, when skiers or boarders take their first turn.


Surface hoar, once buried, creates a weak layer in the snowpack

The decision to “go out early” is always made before anyone actually sets out on the snow. It would be easy to decide when to go out if we had a clear rubric, if anything 5″ or more meant an automatic callout. But it doesn’t work that way. 5″ of light fluff that falls without wind doesn’t add much stress to the snowpack. However, 5″ of wet, heavy snow that comes in on a southwest wind and deposits snow in our north-facing starting zones could trigger big slides. Avalanche hazard is determined by the strength of the snowpack versus the stress of new snow. The snowpack can weaken or strengthen over time. In a maritime climate, such as ours, the snowpack tends to strengthen over time. The stress of new snow is our biggest determinant in avalanche hazard. We base our avalanche control almost entirely on new snow.

Here’s how we make that decision.

Automatic Callout


Hiking the Throne for AC in Southback

If the weather is nuking all day long, and we have not had much skier compaction, Chet, the Snow Safety Director, may decide to make the callout “automatic.”

Regardless of what happens overnight, the determination has already been made before the previous ski day ends. If the upper mountain is on “wind hold” during a big snow event, and no one has been up to ski the new snow, we will almost always have an “automatic callout”.

We set our alarms to arrive early to work at about 6AM. Then we all head up the Gondola and disperse from there to our various routes, each consisting of at least one avalanche blaster and one blaster apprentice.

Crystal Mountain has numerous avalanche paths. We are right up there with bigger areas like Squaw and Snowbird for number of detonations.

At other ski patrols, it may take years for a new patroller to gain enough hours to sit for their blasters exam. At Crystal, new patroller usually get enough apprentice hours in a single season.

Jack’s Call

Every night a ski patroller stays at the Summit House. Back in the day, the late Jack Lewis lived there, and we still refer to the night patroller as “Jack”. It can be a sweet gig with views of alpenglow and starlight or it can be windy and stormy and full of calls to cat drivers and midnight walks along the ridge to the top of Grubstake to determine the snowfall. If Jack determines we’ve had enough snow for AC, he or she will call our Snow Safety Director. If Chet agrees, Jack gets on the phone to wake us all up to come in early.

The Decision

But how does Jack decide? That’s the 5 Million Dollar question. The snowpack is likea layer cake. Sometimes that cake is hard and dense and well compacted. Other times a light layer sits pretty on top of denser layers. We do not usually go out then.

72 Hour Snowfall Total

72 Hour Snowfall Total

When we have dense snow on top of weaker snow, that’s a recipe for avalanches.

Dense snow can come from the sheer weight of the snow–a foot of new snow in any form will almost always bring us out for AC. Dense snow can also be transported by wind onto lee slopes.

A few inches of new snow with just the right wind direction can increase avalanche hazard dramatically. Wind, water amounts and temperature all play a role in avalanche control.

Avalanches happen when the stress on the snowpack outweighs the strength. Those days we wake to the sound of booms in anticipation of great skiing.

Looking Ahead

Ski patrollers are looking at the forecast, anticipating some early mornings in the coming days. It is already snowing as of 8AM Saturday and should continue for the next several days. The 72 Hour snowfall total, above, shows over 20 inches of snow in the next few days. Monday morning could be our biggest day yet. The hills will be alive with the sound of avi bombs.

You Should Have Been Here Yesterday


Forrest breaking trail on the Throne

As predicted yesterday was “The Day” to call in sick and go skiing. It was by far our deepest snowfall to date this season at Crystal, and it finished with several inches of very light powder. While it wasn’t all blower (the high southerly wind from the night before stripped the Frontside and Grubstake) it was pretty darn close.

After completing two avalanche control routes (Throne, which was deep and Brand X, which was deeper), I stood by to open gates at Northway. While familiar faces stomped their skis and listened quietly as I reminded them all to “keep their partners in sight”, I enjoyed the 10 minutes of banter. It is not very often that a ski patroller has the attention of such a large crowd.

It reminded me of two things that I love about Crystal:

  1. The locals: We have some of the most dedicated group of skiers here. Considering that the closest city with real employment is 1.5 hours away, it’s amazing to see people drive 3+ hours every day just to ski here. Perhaps since many of our locals once owned shares in the company we’re blessed with skiers and riders that take ownership in the place. I like that.
  2. The compartmentalization: With both Northway and Southback, we can stagger the opening of our inbounds terrain. This means you can ski powder all day long. If you don’t make first chair so you can rip the Frontside to the envy of all the latecomers you can still be first in line at one of the Northway gates and get first tracks. Some days you can even do the same out South. If you’re lucky you can find yourself at the top of an untracked run on a pristine powder day, not once but twice or even three times. And that my friends is the closest thing to heaven you will ever find. Trust me on this.

Just one tiny little reminder. When you are standing at a gate and a patroller opens it so you can ski that beautiful pristine line while she coils the rope, please don’t stampede her or run over her skis or push her down. Remember, on powder days your true nature comes out. It’s easy to be Mr. Nice Guy on a groomer day.

As an example, here’s a hearty shout out to Joel Hammond. As I rushed to open Gate 10 at Northway yesterday, he told me to wait so he could give me a hug first. Now that’s a gentlemen. High-five Joel. I hope your run in Orgasm Meadows lived up to its name.




It’s snowing hard at Crystal this morning. I think we may have brought it back from Japan. Let me tell you, if a gal has to fly to Japan now and again to make it snow here, then I’m okay with that.

The patrol is heading out for avalanche control (hence the early morning post) and we’re anticipating a busy day. Get up here early.

About 9 inches overnight at Employee Housing

The Best Laid Plans


Sometimes the magic just doesn’t work.

Noone likes wind at a ski area

I expected yesterday to be a blower day–two feet of new snow with more coming in. But the only blower snow was the stuff screaming on the wind. Ski patrollers went out early to throw bombs, and we made it to the top of the mountain just in time for the winds to spike into the 50s. By the time our avalanche control teams were in place, the winds had increased to a steady howl. With winds spiking into the 80s, blowing snow and decreasing visibility, some teams couldn’t even complete their routes. The slopes that didn’t naturally slide on their own went big yesterday morning.

Then the temperatures spiked. By the end of the day, it was above freezing at the base. Fortunately that’s right about the time when the fire hose of precipitation shut off so we didn’t get any rain.

The good news is that today we are expecting a lull between storms. The upper mountain didn’t get skied yesterday and stayed cold enough to still provide some fresh lines in the more protected aspects. We hope to get everything open including Southback so that we can break up this slab before the next storm.

So do us all a favor. Come on up and ski up this new, blown-in snow for us. It beats the alternative.