Summit Weather Windows on Everest - Too Narrow for Safety?

May 13, 2010
Outside Magazine

More teams have made the decision for a summit bid this weekend. Thelatest include the Malta Everest team, half of Peak Freaks and a twoperson team from First Ascent. They are now at camp 2. Why are theseclimbers going to the top in marginal weather? Well maybe the weatherwill not be marginal - at least according to some weather forecasts.

Before looking at the weather, an quick update on the teams. Thereis movement on the north with a large Chinese team leaving base camp.Perhaps to fix the rope to the summit. And Jordan Romero latest postsuggest they may go for their summit bid soon. On the south, the vastmajority of the teams have chosen to wait for a longer weather windowand the teams at C2 are resting up and waiting for the winds to calmbefore going higher.

Patrick Hollingworth posted this update on his climb from BC to C2:

These are some of the strongest winds I have experiencedin the mountains - there is a massive and constant roar coming fromEverest - the jetstream winds are in full flight! The winds wereblowing snow UP the north face of Nuptse (like a reverse avalanche),and a few tents were destroyed here in C2 last night. C3 isuninhabitable at the moment because of the winds, as is C4 on the SouthCol. The winds are however forecast to drop in the coming days, and fornow we're still looking at Sunday 16th for our summit attempt.

Everyone in the world makes the same joke about their local weather."If you don't like the weather, just wait a day." And on Everest it isthe same. The key factor for a summit bid is the wind speed, most teamslook for under 30 mph (48 km/h). This is mostly influenced by theposition of the jet stream which is positioned on top of, or near,Everest almost all year. Historically, the jet moves away for a week orso in mid May as monsoons and typhoons build in the Bay of Bengal, thusthe annual opportunity for summits each spring.

Most top teams pay for a professional weather forecast. Two primary sources are US based and Swiss service Meteotest.These are teams of meteorologists who not only look at the data butalso interpret it and then communicate the forecast and recommendationsto their clients.

Climbers pay for these services and keep them private since it is avalue to their team members and a safety issue. If you have watched theDiscovery Everest series you have seen Russell Brice pour over his datato make an informed decision for his clients.

Every model has a bias built in, or a base set of assumptions, usedto calculate the end result. Knowing how the models are created allowsan informed decision as to how to use the data. Simply reading the datais necessary but not sufficient to make a good decision. Experience isa major factor in the final decision. The professional services utilizemultiple models before making a single conclusion.

However, accessible to any team with an internet connection, whichis virtually all of them, teams can see a forecast from variouswebsites. publishes a well known forecast that isposted on multiple expedition sites based on computer models accordingto their site:

We do not have a magic ball and we do not sell snakeoil. Scientific knowledge of the weather systems and the behaviour ofthe atmosphere is still poor. Be very critical if anybody tells yousomething different! Even the most powerful supercomputers can not copewith the shear amount of data and number crunching that a detailed highresolution model requires

Yet, climate modellers are doing a pretty good job. And we make themost of it, by putting together state of the art modelling tools withour personal knowledge of weather behaviour, and a long term experienceon mountain terrain.

This is meteoexploration's current forecast for Everest and the weekend window teams are considering:

Weather by meteoexploration

Ensemble-himalaya-Everest-FF350 Fromthis chart, you can see a dip in the winds on Sunday then picking backup on Monday in 12 hour increments. From the same service, you caneasily see from the graph to the right why teams including AdventureConsultants, AAI, Himex, IMG and others are waiting for the May 23rdwindow (click to enlarge).

However, some models disagree with this weekend's window duration,thus the opportunity for human intervention.

What if the forecast isoff by 24 hours? Michael Fagin of put it this way inan interview I posted earlier this season:

Q: Some forecasts are posted on the web, the so called grid forecasts. What are these and how accurate are they?
A: These grid forecasts take what the weather conditions will be for anexact latitude longitude coordinate. So the grid forecast will give youthe exact wind speed for the coordinates for Everest. I have found thatthe problem with these forecasts is if the forecast is off say 200miles or so that this can make for an extremely inaccurate forecast.For example. Let us say that  the grid forecasts  says Everest summitwinds will be 30 knots and the grid forecasts 70 knot winds severalhundred miles to the north of Everest. It is not uncommon for theactual forecast to be off by several hundred miles and the real timewinds can easily be at 70 knots over Everest. So the forecast of 30knot wind over Everest vs. real time winds of 70 knots is a bigproblem. Thus, it is important to get some weather professionalanalyzing the forecast models and explaining to expedition groups whatcan happen

Dan Mazzur of Summit Climb posted yesterday that he is looking at 7 different forecast to make their decision.

The big topic for all Everest climbers is the weather.Well, the 7 websites all agree that around the 15th of May the wind isgoing to drop for a few hours, hopefully allowing the Tibetans to moveup and work above 8300 metres and fix the rope. However, the sevenwebsites say that on the 22nd of may the wind is going to drop for afew days, perhaps for, as long as, up to the 25th of May.

Dan goes on to graphically explain why this is important

Everyone is excited about the weather. As we are campedunder Everest, we can see what the weather is doing up there everysecond of every day. And; Please let me inform you, it is not a prettysite. There is a two kilometre wind plume blowing from the top andaccording to several of the seven "Everest Weather" websites we arecurrently watching, the wind is cooking along up there at 138kilometres/ hour. Exposed flesh would probably freeze solid in a minuteor less up there right now, and you would not be able to stand up, justcrawl along on your hands and knees.

Tim Rippel of Peak Freak's feels confident in their choice of a summit window:

This word is bouncing all over the news these days describing the ideal weather window for a summit opportunity. If it is narrow, our thinking is keep the team small. Like Lucille's push for the summit with her friend Domhnall, no line-ups, no problem, she went for it. The small window was a good window, no wind as you can see in her summit photo holding three flags.  Most windows are small, the one we see right now is small but it works for us considering our size, who is also there and our large sherpa support.

So given all this data, what do you do? Well the worse case is for ateam to cherry pick the forecast that tells them what they want toread, the best case is to take the data combined with experience andcurrent observations to make the best decision possible taking intoaccount safety as the primary factor.

Leaders will consult with the Sherpas. Then they must take intoaccount the skills of their team, their experience, their selfsufficiency in case a leader or Sherpa becomes impaired, rescueresources, availability of emergency oxygen and the ability to get itto climbers in need, access to medical consultation via reliable radiosor sat phones and many other factors. But one of the key considerationsis ability to move fast, speed, in case of problems.

Obviously no sane climber puts themselves knowingly into danger; butsummit fever is powerful and can skew decision making. I am often askedwhat is the difference between one Everest expedition company andanother. This is a perfect example. Access to information, experienceto understand that information and judgment to make a safe decision.

So full circle to this weekend and the decision to go up. It appearsmost of the teams have access to multiple weather forecasts, many ofthe leaders are experienced; some with multiple Everest expeditions.They are making their decisions based on the best information that canget. This is what mountaineering is all about, judgment. Some teamshave chosen to wait, others to go.

The best to all the climbers now at camp 2. We are all pulling for you and for the winds to lull as predicted.

Climb On!


Arnette is a speaker, mountaineer and Alzheimer's Advocate. You can read more on his site

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