Predicting Everest Weather: Art or Science?

As regular followers of Everest climbs know, order the weather is the make/break factor for all expeditions. And the forecasts are critical for the safety of teams. While it may seem straightforward given the success rate we see in modern times, medical predicting the weather is far from a science as this interview with Michale Fagin shows.

Michael provides weather services to many Everest expeditions as well as for other adventures around the globe from his company everestweather.com

Everest teams spend thousands of dollars to receive expert forecast throughout the expedition. Many leaders are now weather experts in reading forecast maps and interpreting the data.

However, it is the weather professionals who monitor the data from all around the world to feed these leaders the information possible. In the end, each team makes their own decision based on data, observations and their own experience and instincts.

After all, a wrong decision can put lives at risks. Weather services is a major factor is selecting your team on an Everest climb.

The 1996 disaster on Everest was mostly blamed on a surprise storm that moved up the mountain. I asked Michael about that a couple of years ago and he told us that although this storm was a surprise to the climbers that did not have access to forecast, a trained weather forecaster would have seen (from forecast maps) a big storm coming in several days prior to this tragedy.

Q: The famous 1996 Everest storm that claimed 12 lives is said to have come up from the lower valley and rose onto Everest. Was there anyway to forecast that event?
Several years ago I did look at some archived forecast maps for the day of the day storm on May 10, 1996, and forecast maps for several days before the storm. This was a typical strong storm pattern that can occur at Everest. There was a deep upper low pressure that was moving in from the north and west and this brought moderate precipitation and strong winds. Estimated winds of over 100 knots. If I’m not mistaken after this tragedy that the Imax team, who was at a lower camp,  decided to hire the first weather forecast for Everest and I believe they used a European firm for the forecast

I wanted to see what has changed for 2010 and what the teams could expect. Once again, Michael shares his insights:

Q: We always hear about the Jet Stream ’sitting” on top of Everest year-round. Does that change in a large way year to year with effects like El Nino or something else?
Actually during some El Nino years (like now) there is a strong southerly branch to the jet stream. What this means in the US is that California can get hammered with storms and this has been the case for this late winter and early spring so far. What this means for Everest is in some past El Nino’s the southerly branch of the jet stream can stay over Everest for an extended periods of time for strong winds. Perhaps well into May. We will see what happens this season

Q: What is the lowest winds that climbers will accept for a summit bid?
I’m told by climbers that under 20 knots is good, under 30 knots is acceptable.

Q: In terms of forecast accuracy, how would rate Everest predictions for wind accuracy?
When the jet stream is over Everest the forecast models do a good job. However the models tend to do poorly on the re of the jet stream. Many times the models want to have the jet stream exit the region faster than it actually does. Also when there is a big snow storm over Everest the models do very poorly. In fact the models do poorly in general on predicting snowfall.

Q: What is the forecast duration?
Generally 1 to 3 days the models for winds can be accurate.

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

Q: Any new techniques for 2010?
Just continue to monitor the tropics since over the last several climbing seasons there has been a tendency for storms to form in the Bay of Bengal and then move north towards Everest. When this occurs this  tends to bring copious amounts of snowfall and it did occur May 25, 2009

Q: How is Everest weather different in the spring compared to the Fall climbing seasons?
During the spring the major focus, besides the big storms out of the Bay of Bengal, is when the jet stream shifts to the north which can make for good summit wind conditions. Climbers want a heads up on this. For the fall climbing season one is looking for the re of the monsoon and associated precipitation. The re is to the south of Everest.

Thanks Michael. I know we are all hoping for the weather window to open up as usual in mid may for a clear summit.

Dispatches from the teams are bit slow today while they go through villages without internet cafes. Most are now using satellite phones to update websites and social media. But all is going well from what I am seeing even the north side teams are now leaving Kathmandu for Tibet. More details on one climber following his father’s footsteps tomorrow.

Climb On!

Alan