Accurately Estimating Wind Speed

47-70 km/h, not mph That's 29.2-43 mph. Watch some of the Hilleberg wind tests for some serious deformation.

I wonder a lot about that too. Whenever someone mentions a wind speed, I imagine myself standing on a truck moving at that speed, and usually conclude the person was exaggerating or misinformed.

Ed – I think you're mistaken. The winds were 40 – 76 km/hr. The max translates to 47 mph hour as I initially stated. My point being that even that max wind speed is pretty tremendous and perhaps at times our estimates are somewhat overstated.

That's a good way of viewing it Corbin. I didn't equate it to standing on a moving vehicle. I may use that as a gauge in the future. good stuff. thanks!

A few weeks ago we had 100km/h plus winds in our area.
The worst was during the night, I woke up a few times because we have a large Norfolk pine just over the fence, large enough to crush our house.
As it turned out we were the only ones of our immediate neighbours not to have the roof and or fences damaged. (thanks pine…)
The next day was still a bit windy so we went for a walk.
My wife commented how we were still having good enough gusts for me to set up a tent to play with it in the wind.
I told her that no it wasn't good enough.
So I pulled out my Kestrel , the gusts were at around 15km/h….
yes most people over estimate wind strength.
BTW, the Beufort scale helps :
http://www.bom.gov.au/lam/glossary/beaufort.shtml

I agree that it is pretty windy. It just gets confusing going back and forth between mph and km/h Remember that a kilometer is .6 mile. So 70 km/h is almost 43.5 mph. More important question is where are the additional guy lines? Just the two pull outs on the side are being used. Could certainly use more further up.

In those conditions the tent did very well.
people that talk about having had 100MP/H on their tents are kidding themselves and misleading others.
I am talking about the typical hiking tents we discuss here not geodesic type base camp tents…

I live in a part of the world where wind is so prevalent that trees actual grow on an angle. Search "tuckamore" in Google Images to see. We generally have winds over 100Kmh half a dozen times a year, with certain areas getting winds over 100Mph as many times each year – search "Wreckhouse" Newfoundland, where transport trucks regularly get blown over onto their sides.

It is now 50Kmh winds outside at 0700 in the morning and as I came to work it felt just "windy," but based on my experience on a recent trip it feels a hell of a lot stronger in a tent. I was recently in a HMG Ultamid 2 (Cuben) in 60-70Kmh winds (assuming the weather forecast was accurate) and while we managed to keep it standing with constant adjusting, it felt unsustainable and very unhealthy for the tent. I having never been in an unsheltered tent at those speeds before, and was astonished at how much windier it seemed. As a gauge, it felt like a 100 plus Kmh storm that would tear the tent apart. Ultimately we moved off the lake shore and into the forest for shelter.

Mind you I am a pyramid novice and expect I have much to learn about pitching it properly and expect it is stronger enough to sustain higher winds. I don't think I could sleep in it though!

Derrick

Hi Franco

Try walking across Betts Camp in bad weather.
When you manage that, try carrying skis across there.
From memory, top speed there may have been 243 kph.
We have had to crawl across a few times.
No, we did not camp there!

Cheers

Is something like 30MPH gusts more likely to be the danger zone for 3-season UL tents and tarps?

For example, my Big Agnes Fly Creek UL3. With the light poles, I imagine it'd be relying pretty heavily on use of all the guy lines in the wind. I've never been in severe wind in it, just heavy rain.

I like the Beaufort scale, with just a little memorization it can calibrate your wind "sensor" pretty well. I've experienced "gale" force winds on a cruise where I could lean 45 degrees into the wind and not fall over. Walking into the wind was exceedingly difficult. This is about on par with what the OP video shows. Here in AZ we get a lot of wind due to all the canyons and rugged terrain. Our high peak of Mt. Humphreys gets enough wind to require crawling sometimes, similar to Roger's experiences.

I'm surprised so many people over estimate wind actually. According to the beaufort, strong winds are only experienced when using an umbrella is a PITA, which seems about what I would call strong. Maybe it's just the fact that that is only 30mph that throws people off? I know I wouldn't want to hold an umbrella outside a car window at those speeds.

Fun fact, like someone else mentioned, that's how I test the accuracy of 'wind proof to XXmph' on a lot of gear. Stick my arm out a window on the freeway and see just how wind resistant it is.

Yep, that's how I do it too Dustin. Arm out the window. At 50mph it's tough to move your arm forward. A 35mph wind on most everyday 3 season tents is a lot of breeze.

I remember we had 85mph straight line winds once back in college. It was literally scary being outside in that amount of wind. Watching the trees sway it was hard to believe how they didn't all come down.

Ryan

My personal Aleutian Island wind scale:

Nice day – 40 mph

Door blows off pick-up truck – 70 mph

Flattened 55-gallon (imperial 45-gallon) drums go airborne, scaring this engineer – 100 mph

Just stayed inside that day – gusts to 126 mph (206 kph).

I do a lot of field work and have chased a lot of coffee cups and field-log paper around in the wind. Dutch Harbor was the only place I've been where pipe wrenches blow away.

Hi David

Um … interesting wind scale you have there. The idea of airborne pipe wrenches …

Cheers

At what wind speed will the most storm worthy winter tent (that's packable) have it's fabric ripped apart?

> At what wind speed will the most storm worthy winter tent (that's packable) have
> it's fabric ripped apart?
Not a simple question. There are a number of obvious factors, and a number of less-obvious ones too.

Let's start by limiting the designs to be considered: serious geodesic domes with lots of poles, and tunnels. Pop-ups and tarps need not apply.

Obvious preliminary question: has the fabric suffered any UV degradation?
Examination of the remains of tents on the South Col of Everest shows the fabric in tatters, consistent with them shredding due to the UV degradation they get up there. Let's assume fairly new fabric.

A major factor is the detailed engineering design of the tent. If there are large unsupported fabric spans the tent shape will distort and collapse. If the poles form long unsupported spans they can buckle and collapse. Both of these factors are discussed in our series on Tunnel Tents.

I should not need to mention that all the poles must be fully sleeved in the fly. Designs where Velcro tapes and hooks etc are used simply do not survive. Tents where the inner has the poles and the fly is thrown over the top are total non-starters. They simply do not feature. Again, see our series on Tunnel Tents.

Then we come to guy ropes. We will ignore the 'free-standing' category here as irrelevant (that's me being polite). Guy ropes need to be placed on the tent with some consideration. Typically they are used to support the poles against the wind, so they need to be placed with some engineering knowledge. Some tents have guy ropes in the middle of fabric areas. Most (not all) designs with such guys are for mild weather only.

Guy ropes are no use without firm stakes in the ground. If a stake moves, you have trouble. I will add here that some tent designs need stakes not only on the guy ropes but also on the corners of the tent: where the poles hit the ground. Tunnel tents are critically dependent on the two upwind corner stakes: without those being rock-solid, big trouble.

Where you pitch the tent also matters. Any shelter helps; pitching in the middle of an open saddle (this may be spelt 'funnel') does not help. Me, I favour just downwind of a copse of trees. They slow the wind without creating turbulence.

A much less obvious factor is how tightly the tent is pitched. After UV degradation, the number one killer of tents is probably flapping. If the fly is loose, the flapping will eventually rip out the guys and shred the fabric. That is why I place so much emphasis on guy ropes and stakes.

That will do for now.

Cheers

If you really want to go there you can get hand held meters like the Kestrel line : http://kestrelmeters.com. Another excuse to burn up a couple hundred bucks and more weight in your pack.

I like the Beaufort scale, but the orientation is more to seashore clues rather than some desolate spot above tree line. We need stuff like: "tent mate screams for his mother: 100-110MPH"

I head in when the seagulls are flying backwards :)

Many tents will not withstand strong winds. This was filmed on the Isle of Skye (sea level), from a Trek T1 tunnel tent:

http://youtu.be/r4NN3cltuuY

It doesn't even look that windy to me in the clip – the waterfall would be blowing upwards if it was really windy. I think the tent just wasn't pitched well. So much for 'free-standing' tents.

Winds get stronger as you go higher. 173MPH has been recorded on the Cairngorm plateau at 4000ft (there is a weather station there).

As we speak about measuring wind speed , I am reminded of (and send prayers for) the people of the Philippines, who just had to endure a hurricane with recorded sustained winds over 200mph… and at sea level. – a bit more force than at 4000ft, if I recall.

It may just be the most powerful storm in recorded history.

Matt

Hi Stuart

Well-known video.
Dunno what they were thinking when they pitched it, but whatever they did was seriously wrong. The thing is as loose and flappy as all blazes. That it survived that long is remarkable.

What's also remarkable is that the camera man just sat there filming, rather than trying to secure the tent. Very odd.

Cheers

Did the wind blow his pants off too?

In North Dakota a log chain tied on a pole is used for measuring wind speed.

Breezy-> chain moves a bit

Windy-> chain moves out to a 45 degree angle

VERY windy-> chain links begin snapping off the end

Hope this helps.

I actually wrote some of the original code for the automatic weather station on Cairngorm as an undergrad. Some of the measurement data is available online at http://cairngormweather.eps.hw.ac.uk

On 3rd Jan 1993 the highest ever recorded gust was 175mph (55.0m/s) with an average of 123mph over the measurement period. The temperature was -3.0C
Four hours later the gust speed was 160mph with an average of 120mph, and the temperature had gone down to -6.4C

Not especially cold by US standards perhaps, but in combination with that windspeed…
lethal.

I have a slightly different windscale but I have to say not anywhere close to 200kph

If it picks up a 110 kilo bloke wearing a 30 kilo rucksack [ Me] and drops him 3 metres away I reckon the wind is about 120klicks or greater, if the same bloke needs to crawl along the ground using an ice-axe it’s about 160 or greater