Field Notes: Retreat from a Spring Alpine Storm

[Ryan Jordan]

Not at all Peter – my preference for a winter and desert shelter when I’m expecting wind is my Locus Gear Khufu with a solid nylon inner tent.

[Eric Blumensaadt]

Very interesting video, “the good, the bad and the ugly”. Packing up at midnight could not have been fun in that wind-blown snow.

If you had a 4 season tent spindrift inside the tent would not have been a problem but keeping poles and deadmen in place is still a fight with any tent in that situation. The AEON was not made for that kind of extreme winter weather hence the spindrift inside coming through the perimeter ventilation mesh. In a heavy snow without the wind it would have been fine as your review view shows.

I’ve had my TT Moment DW, W/ ripstop inner tent, in one very fierce storm and no snow came inside.. I had to close both end  flaps, fly flap and inner tent flap, on my head end which was also the windward end. The storm seemed like it was snowing hard but in the morning there was only another 8 inches. Wind can be deceptive. I would say I experienced 40 mph gusts and 25 mph steady winds.

UPDATE:

Christoph Blank’s account with his Moment DW was similar to mine last week (except mine was in a nearby park for testing purposes).

My Moment had the following:

1. internal (under the fly) Crossing Pole
2. four fly hem stakes
3. four guy lines – one on each side of the main hoop pole and one at each end

Still, with recorded 60 mph gusts and steady 40 mph winds, one of my fly hem stake loops tore off (hand stitching broke).

REMEDY: I have removed all the fly hem loops, put 2″ circles of Tenacious Tape at the stake loop points (1/2 of the circle on each side of the area) and had the stake loops re-sewn with a sewing machine in zig-zag stitching. Hopefully this will be a stronger attachment.

Otherwise my tent held up very well in the high winds. I’m satisfied I could have stayed in the tent all night in those conditions.

 

 

 

[William Chilton]

“Because this is supposed to be. 3-season tent.”

When manufacturers designate a tent as 3 season, I’ve always taken it to mean not for use in snow, rather than literally  for use 21 March to 21 December regardless of location and altitude (or similar in southern hemisphere). :)

Regarding the grommets, is it right to assume that the pole tips were able to push through the snow and this contributed to the problem? Would the forces on the grommets have been less on solid ground?

[Monte Masterson]

If it hadn’t been for the cord failures, the Dirigo 2 may have held up throughout the night. The first issue was with the linelocks (hate em) as the cords slipped through them. This allowed movement and play on the shelter which then brought on the violent buffeting and jerking which occurs when a tent isn’t drum tight in such a scenario.Then added to it was the issue of Ryan’s inadequate cords breaking. And as William says, the pole tips not contacting solid ground probably helped the grommet failure even more.

One of the criticisms of the Dirigo 2 has been the way the floor is sewn directly to the sides with no mesh in between. The spindrift would have been even worse with more mesh.

I’m just not sure this was a fair test for the tent. I totally get pushing the limits in order to probe for weaknesses, however, I see this as kind of like taking your stock 4 X 4 pickup to the Baja 1000 and then pointing out the broken pieces afterwards. It wouldn’t shine a fair light on the vehicle. I do applaud the ultimate test approach though. I’m just afraid that there are critics of the tent who will say “see, look, weak pole grommets, I knew it was a poorly designed shelter.”

[rmeurant]

The problem with the Dirigo in my opinion is more deep-seated, and essentially a design flaw. The structural form reduces to a three-pole compression structure held in place by a tensile envelope. This analysis reduces the top horizontal structural component to the equivalent of a short pole (compression strut).

If the two joints between top pole and two vertical poles were pin-joints, the assembly would be manifestly unstable. Therefore, those two joints need to be rigid. They need at the very least to prevent twisting of one joint relative to the other about the horizontal axis of the top pole. Ideally they would also prevent rotation of either joint  in the vertical plane so that the angle between long pole and short pole could vary at either joint.

This means the assemblage is structurally unstable; its default form is an unstable equilibrium where any displacement is not inherently self-correcting, but is only constrained by the tensile skin. Once rotational distortion starts, the forces tend to increase that distortion, until the pole strength, joint constraint, and tensile stress are sufficient to restrain the distortion. It is also problematic in introducing two rigid elements (the joints) into a tensile form that by its nature ought to be flexible to a degree to accommodate imposed forces.

The two long poles function as compression struts that are in effect pushing against one another via the top pole. Their natural response to imposed stress is to rotate the two top points of the long poles about the vertical axis. I think that would be the first mode of deformation. The second mode would be distortion in the vertical plane, so that the top pole rotates in the vertical plane as one end/joint lowers while the other rises. As well either long pole could be expected to curve under extreme stress.

Neither deformation mode is healthy, as it can only be withstood by the presumed rigidity of both joints, and the tensile form straining to return to its normal state.

I can’t imagine any such rigid joint configuration would be suitable that relies on introducing a trekking pole, without being cumbersome and bulky, and undependable in the field.

By contrast, the Locus Khufu/ Duomid with two long poles and pin-joint at the apex, together with base tensile tie, is stable. In addition, the Khufu would have a little less windage than the Duomid, by virtue of its slightly less dimensions.

I mean no disrespect to HMG.

[James Marco]

Yeah, I pretty much agree, William. But, snow wasn’t the main issue. Ryan said that the actual sky was clear. People pushing light weight gear to the limit and beyond can be a problem. While Roger was likely laughing at this, this is actually a fair test of this gear. Ryan was surely not anticipating the heavy winds he encountered nor the heavy “ground blizzard” he encountered due to the wind.

Site selection is always a concern with any lightweight/UL gear. Ryan intentionally chose the windiest spot in the immediate area for this video. I am sure he was more interested in testing the overall limits at which a Dirigo could be used. I would set this as 40mph with an occasional gust above that. Snow? Well, a minor problem that wasn’t really tested. Weather rarely cooperates, even when you WANT crappy weather…you don’t get it or you get too much. In this case, it threw Ryan a curve, a 65+mph curve. Like I say, I have been out in similar and all I could do was simply roll up in my tarp (like a bivy.) But, I was more interested in tree’s coming down on me and woke up with every freight train gust… I don’t know of any three season tent that would have fared any better in the wind/gusts reported.

Offhand, IFF the weather had held at 40mph, I think he would have been fine. The spin drift would have been annoying and likely couldn’t have been avoided, despite banking in around the perimiter. His cords were quickly found to be too light. Ryan needed some sort of solid connection to his tent, without the plastic line-locks. 1mm line was simply too light. Whether a solid connection could have caused a panel failure in the tent, is questionable. I think a couple bungies (hair ties) would have prevented that. I have had some trouble with spectra line, especially the lighter lines. I think the lightest I go these days is 2mm for bear hangs with some 2.5mm line used as main guy lines (from the peak down, at the corners) as I gradually switch over. The other tie outs on the tarp are still short lengths of 50pound test braided fishing line. These still work fine. I do not use plastic connectors at all…it seems they always slip. ‘Corse then you have to reset them for the next gust…

For solo use, the Dirigo is likely good for 3 season conditions, but very heavy at 1.75pounds (1pound 12oz or 28oz.) This is well above the 1 pound cut-off for a UL shelter. For two people, it is likely OK. This leaves about 14oz per person, which is good weight for UL. The foot print is actually fairly generous for two average sized people. But, the floor means you cannot dig a hole for excess water. Cooking means grabbing a rock or log piece to set the stove on, and boil-overs/spills are always a witch.

As always, weight, volume, and usability. Weight to carry hurts this shelter. Like many other solo hikers, I use a larger 1+ or 2p shelter. I regret small shelters a lot more than I regret carrying three extra ounces. But, more than 12oz more not counting the 8 stakes?? Hmmmm… Volume for the Dirigo is very large, about 9.5L by the specs. My tarp packs up into 1 liter, the size of my pot. Soo, not only is the internal volume of the Dirigo about a half the size of my tarp, it is 9x the carry volume! (I carry a 35L Murmur mostly in 3season weather.) The usability in rainy weather is about even. It is definitely a big plus to be able to cook under a dry roof. Pitching the door out/up a bit gives you necessary room. Packing in the morning is easier under a larger shelter. In summary, the weight is OK. The carry-volume is high. Usability is good. (Unless you encounter a 65+mph wind…) Less than ideal factoring in these three. Storm-worthiness is fine for a three season shelter. Dual doors, are a nothing, for solo use.

Yeah, I agree about the grommets. A simple short loop stitched to form a pocket would be lighter and more rugged. Something like this:

[Nick Gatel]

Because this is supposed to be. 3-season tent. It is April, after all.

Ah, marketing :)

We often equate a 4 season tent to be able to handle winter weather: snow loads and extreme winds. Where I most often hike the worst winds always happen in the spring (April and May) and no snow — winds that are often stronger than what Ryan experienced

In my old age with minor arthritis and a couple fingers that sometime get stuck in the closed position due to a dislocation from a rollerblade accident 6 or 7 years ago I have grown to appreciate LinLoc 3 tensioners — I have installed them on all my shelters — but I use 3mm cord on all of them. This cord is a “little” heavier but doesn’t slip. I’ve had light 1 mm cord break too. For me, anything under 3 mm is “stupid light,” as coined by Skurka, and verified by personal experience in high winds. Also, I use long Easton, Ground Hogs, or Snow stakes (for really sandy soil). It’s crazy that UL hikers want to save weight with light cord and itsy bitsy stakes. Been there and done that too.

Sounds like the guyline tie-outs held up in Ryan’s tent. So even though the shelter was used beyond the conditions stipulated by the manufacturer, the failures were self-induced and the shelter cannot be criticized for this. Had 3 mm cord been used and properly staked, which looked like the deadmens were, the grommets probably wouldn’t have failed and Ryan wouldn’t have needed to bail, assuming the spindrift wouldn’t have necome too problematic. No disrespect for Ryan, he was testing and pushing a shelter beyond its limits — the kind of testing BPL used to be famous for and I would like to see more of this kind stuff like we had in the “old days” of BPL.

Anyway, good work on the video and testing.

 

[Brad Rogers]

As far a linelocks and guylines go – the guys at Trek-Lite who packpack primaraly in England and Scotland (ie high wind is the norm) all seem to use 3mm line with linelock 3’s – I’m sure they don’t do it just because they want to carry the thicker cord.

I’ve had my Duomid is some pretty nasty wind, but probably not 65mph wind (I don’t carry a wind meter and humans are awful judges of wind speed.  The worst problems seemed to be the lightweight cordage, which could be remedied and the spin-drift, which obviously the Dirigo isn’t meant to contend with, nor is any other shelter with much mesh.  Of course, in summer, you want the mesh so the only way to get the best of both worlds is a modular system with both a mesh and solid inners.

My own personal experience with HMG is that their construction is top notch, but I do sometimes question their design decisions.  If the proper cordage was used and there was no snow (which the Dirigo wasn’t designed to contend with), other than the grommets, the tent did survive the 65mph winds without a catastrophic failure which is about all you can ask for in a UL tent.  For reference I have seen a report of a Duplex failure in 65mph winds where the entire corner ripped off – to be fair, it wasn’t designed to be used in those conditions, but just a reference point.

[Brad Rogers]

BTW- I should add that I thought it was a really well done video.  I normally wouldn’t watch videos like that all the way through, but this one kept my interest all the way to the end.  It had a very professional look to it.

[Richard Nisley]

Robert,

Thanks for your detailed shelter structural analysis. It would be easier, for us with less expertise in this discipline, to understand if you could augment your narrative with some simple images.

Also please compare and contrast its structural analysis vs the HMG Ultamid 4.

 

[Ryan Jordan]

Robert – in analyzing slow motion video of the tent, rotation of the pole assembly caused slack in panels, those panels scoop wind, more force is delivered to the stakeout points, guylines slip, and so goes the feedback loop that eventually results in the loss of any structural stability.j

You don’t really see this in a small mid, but in large mids, strong winds do create a bit of panel slack on the downwind side. This dynamic loading and feedback loop is the general mode of failure for most ultralight tents, because they do lack the structure required to keep panels tight.

[Sam H]

Sounds like quite an adventure at least! My deep winter set up for BWCA camping in MN is decidedly NOT UL, lol, but this video sure made me appreciate it! I’m curious what pack you were using actually, I really really like the look of it. Seems to have all three features I’m looking for. Can you tell me what pack you were carrying?

[Brad Rogers]

Sam, I’m pretty sure the pack was a full woven spectra McHale.

[rmeurant]

Thank you Richard for your response, and Ryan for his comment about rotation. I’ve taken another look at the 3 videos on the HMG site of the Dirigo, and they confirm my opinion. I disagree with Rich Rudow’s continued assertion in Video 3 that the 2-pole and CF horizontal member together make this an A-frame construction. It is not. An A-frame would have two primary sloping members that were joined at their intersection by (normally) a pin-joint, which is how the Locus Khufu and DuoMid function when using two poles and an adequate pin-joint connector at the apex (such as the Locus DPTE).

In the Dirigo, the two trekking poles and CF cross-member may be abstracted to a 3-pole structure, with two braced joints to provide rigidity, as on the right:

Left: True A-frame, as per Locus Khufu/DuoMid with two-pole setup, DPTE/pin-jointed at apex.

Right: Dirigo: Pin-joints at base of poles, braced rigid joint at joints at top of long poles/ends of top CF assembly.

Presumed 1st mode of Structural deformation of the 3-pole system (Dirigo):

Left: Plan view of the abstracted 3-pole structure at equilibrium (below), and under load that exceeds the effective constraint of the CF cups of the top assembly (above).

Right: Elevation of the abstracted 3-pole structure at equilibrium (left), and under load that exceeds the effective constraint of the CF cups of the top assembly (right).

(This can be imagined as sitting down, holding two poles with tips on ground, and with a foot ruler held between the tops. Pushing the long poles together will briefly hold the top ruler, but in a highly unstable configuration. With more inwards force, the pole tops rapidly depart from the common vertical plane, and eject the ruler. It is not a self-correcting system.)

Under load, assuming no movement of the bases of the long poles, the 3-pole assembly twists about its vertical axis. The CF top assembly has to prevent the long poles from rotating and also ensure that it does not twist (along its longitudinal horizontal axis) under the applied torsion.

Presumed 2nd mode of Structural deformation of the 3-pole system (Dirigo):

Under load, the transverse vertical axis rotates. Even with extreme rigidity of the joints, the long poles will bow (curvature not shown).

[Also with regard to the various rectangular and square pyramids, in plan, their tensile form should not in my opinion be analyzed as rectangular or square, but as either (stretched) octagonal or hexagonal, depending on whether there is a mid-edge anchor on the short side. This is quite noticeable in the Khufu; the mid-long side anchor points are quite extended from the theoretical rectangle plan mid-points. This also gives better fore-and-aft stability to the rectangular mid.]

[Nick Gatel]

Yeah, it’s a McHale. Very similar to my LBP 36, which is full Dyneema with a Spectra bottom (the bottom is a little heavier/robust). The shoulder strap pockets, hip belt pockets and water bottle pockets on Ryan’s pack are from McHale also. Mine is over 8 years old and is vertually indestructible and carries like a dream. Best gear investment I ever made. I have a smaller McHale Bump too short trips, which is 7 years old.

 

 

 

 

[BlackHatGuy]

Nick, one of those pics has me confused. Did it snow down in Palm Springs? :-)

[William Chilton]

Above I asked the question, “Regarding the grommets, is it right to assume that the pole tips were able to push through the snow and this contributed to the problem? Would the forces on the grommets have been less on solid ground?”

I think these are important questions in regards to the Dirigo. Was the grommet failure due to vertical forces or due to sideways forces? Would the failure have occurred if the tent had been pitched on solid ground?

I think it would be useful to know since if the failure was due to vertical forces on snow, a bottle top or similar under the tips might be useful for anyone using the tent on snow or soft ground. If it was sideways forces, then it is more worrying, though perhaps the pole tips on solid ground would resist the sideways force without putting as much strain on the grommets as when on snow.

Since the grommets were the only failure of the tent (rather than added 1mm cord) in rather difficult conditions, this would be good to learn.

[eric stephenson]

Thanks for sharing this. Looks like a cold night out and excellent test of that little tent.

For winter cooking in a shelter I like the MSR Reactor Hanging Kit – gets the stove up off the snow and coaxes better performance out of it. Also reduces the risk of knocking it over.

I didn’t notice a shovel in your video. I know it adds weight, but I always take an aluminum-bladed avalanche shovel (small one) on Nordic ski tours. Makes the placement of dead man anchors, and their retrieval in the morning, so much easier. Also a good safety net if you have to dig a survival shelter.

It’s not “ultralight” at 3 lbs, but I’ve had the opportunity to handle an MSR Advance Pro 2 tent and it is excellent for exactly the conditions you encountered.

I’ve shot video on winter trips and it is hard, cold work when you’re trying to get routine tasks done. Keep up the great work!

[Patrick Podenski]

Ryan didn’t have a shovel, but he did have one of those plastic scoops that he used to dig out the holes for his deadman anchors. With that setup he didn’t need to dig up the deadman sticks, he would just pull the cord out, so no need for a shovel in the morning.

DCF is somewhat sensitive to heat, so I do wonder if a Reactor hanging kit would bring the stove heat too close to the tent material? I know that when the pot is on the radiant burner, there isn’t a whole lot of heat rising above the pot due to the very efficient heat exchanger built into the pot. When the pot is removed, a fair amount of heat would rise though. I don’t have direct experience with applying too much heat to DCF because I have been able to just cook outside. In a big storm one would most certainly want to cook under the shelter with adequate ventilation. I usually have a thin pad underneath the stove to keep it off the snow. Also good to avoid getting lots of snow on the bottom of the pot.

I wonder how many people will end up using the Dirigo in winter conditions? Perhaps with strong cord and well-anchored it would do better?

[Monte Masterson]

Ryan, you’re approaching 10,000 views on this video in just 5 days. You’ve also gained 600 subscribers in that same time period. People love harrowing drama and adventure.Those numbers could grow exponentially if your subsequent productions are good enough.

Most YouTube videos are boring as hell, but this one wasn’t. Viewers want to be entertained. Just look at how many views Shugemery gets talking about Winter hammock camping in freakin Wisconsin.

 

 

 

[eric stephenson]

<p style=”padding-left: 30px;”>”DCF is somewhat sensitive to heat, so I do wonder if a Reactor hanging kit would bring the stove heat too close to the tent material?”</p>
That’s a good question. It wouldn’t do to burn the tent! This reminds me that a new fuel canister will often flare up, so in any event it’s always wise to do your first lighting of a new canister outside the shelter. And ventilate.

Regarding performance of the stove, I’ve also had good luck putting the canister in a Sea-to-Summit bowl with a little water.

I may have one more ski tour in me before thoughts of summer trips take over.

Ryan – May I ask if the video was shot using Moment lenses on a smartphone? I’ve been looking at Moment reviews – might replace a mirrorless camera with iPhone video. Listened to BPL Podcast #6 last night. Enjoyed it. Moment lenses were mentioned.

 

[Craig B]

Hershey’s Special Dark?  Seriously?!  We’re in the golden age of craft dark chocolate and you go with that?  It’s not like it’s hard to find either, as even Trader Joe’s has better.  Ryan, do yourself a favor and try a nice 70% bar from somewhere else.  Here are just a few widely distributed options: Alter Eco, Chocolove, Equal exchange, Vahlrona, Scharfenberger, Green and Blacks…..

[peter t]

William et all,  “Regarding the grommets…

Max Neale wrote about similar Dirigo grommet failures, here: http://maxneale.blogspot.com/2019/04/hyperlite-mountain-gear-dirigo-2-ultralight-tent-shelter-review.html

[Erica R]

Seems the site selection was made for the video. It really makes no sense to camp on an exposed ridge with a storm coming in.

[eric stephenson]

Camping on a ridge is usually the way to go during spring ski tours. You want western/eastern exposure to the sun. You can’t overestimate the benefit of sunlight on your tent at altitude.

However, given the forecast and tent selection . . .

[Author]

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