Bestigning af Mustagh Ata (7546 m), Xinjiang, Kina

28. juni - 24. juli, 2004

Side 1 2 3 4 5 Diverse

klik på sidetal for valg af side

Nedenfor linkes til diverse informationer m.m.:

 

Daglige updates fra Jon Otto (SummitClimb.com) via satelittelefon til EverestNews.com

 

Daglige updates fra Ted Callahan (Mountain Madness) via satelittelefon til EverestNews.com

 

Analyse af årsagerne til det usædvanligt dårlige vejr fra NASA meteolog og ekspeditionsdeltager Bob Oglesby

 

GPS koordinater af vores lejre

 

Download vores udstyrsliste i Excel format

 

Omtale af vores ekspedition fra Luksus Freestyle Magazine #11, side 12, 2004

 

Omtale af vores ekspedition fra bladet Klatring, april, 2005

Analyse af årsagerne til det usædvanligt dårlige vejr fra NASA meteolog og ekspeditionsdeltager Bob Oglesby

 

The Wacky Weather on Mustagh Ata July 14-19 2004: An Analysis
As most of you know, we suffered a prolonged, 6 day snowstorm on Mustagh Ata from July 14-19, followed by more bad weather July 21-23. This was not a small scale event; northern Pakistan and much of western China suffered from the same storm.


I’ll start with a summary of my personal observations. On Mustgah, I first noticed a change in the weather the morning of Wednesday July 14 at base camp, with low stratus clouds across the Pamir plateau, and fairly warm (for 14,500 ft) relatively calm conditions. More ominously, the flow seemed to be from the east or southeast, rather than the southwest to northwest as in previous days. During that day, conditions were not too bad; I hiked up to Camp 1 in the afternoon under partly sunny skies. But that night in Camp 1 it snowed heavily all night (I repeatedly had to shake snow off the roof of the tent). Temperatures were quite mild for that altitude (17,600 ft) and there was almost no wind – just the heavy snow. The next morning (the 15th) the snow tapered off and the sun peeked through the clouds occasionally, though it remained calm and mild with a southeast flow. About 2 pm, it became overcast and began to snow very heavily again, with essentially whiteout conditions. The remainder of the Mountain Madness team struggled to Camp 1 under these conditions. Later that night the snow tapered off again, continuing a pattern of approximately 7-8 hours of heavy snow followed by improving conditions for 7-8 hours, then snow again, etc, a pattern that persisted throughout the storm. The morning of the 16th it began snowing hard again and at the advice of our Tibetan ‘sherpas’ we did not even attempt Camp 2. It snowed once again all that afternoon and night, with spectacular thunder and lightning, and the following morning (the 17th) was our last shot at Camp 2 and then the summit. Even though at that point something like 6 feet of new snow had fallen at Camp 1, we did try but only got up a few hundred vertical feet under windy conditions with blowing snow before Awang, one of our Tibetan sherpas, said it was too difficult, with which I agreed as I was already struggling and falling behind. (The trail broken by Awang was largely filled in by the wind within the 10 minutes it took me to reach it.) So we turned back, alas giving up our summit attempt, and went back to Base Camp.


That night, even at Base Camp it snowed heavily (about a foot fell) and the weather remained poor especially up the mountain all that next day and the day after (the 18th and 19th). On the 20th the weather appeared to break, with the wind finally backing around to the north. Too late for us, but a mass movement of other groups began to the upper camps. However, by the afternoon of the 21st the weather turned bad again, with the same south-southeast flow setting up. It snowed again at Base Camp the night of the 21st, and the weather remained poor the next day when we headed back to Kashgar. Kashgar is semi-desert, and only receives about 180 mm of rain per year, yet all night of the 22nd and the morning of the 23rd it rained steadily. It continued to rain up until we had to catch our flight out to Urumqi (fortunately Kashgar only has a few flights so no delays!). We joked that Kashgar received half its annual rain just that day! (More likely it received 25-30 mm, i.e., about an inch). I understand that the weather did start to improve in subsequent days, but I was already on my way home by then.


So what happened? While on the mountain, I kept saying that it looked like the monsoon flow had come up to us and that while no one big storm system plagued us, little ‘ripples’ or short waves in the flow every few hours brought the bursts of heavy snow. Upon analyzing the situation, it appears this is indeed exactly what happened. One does not expect the monsoon moisture to make it as far north as the Mustagh Ata-Kashgar region, so this was a fairly anomalous pattern. This same bad weather also plagued the Karakorum range of northern Pakistan (and the many climbers on K2 and G2). Kudos to the Pakistani meteorology bureau, which unbeknownst to us at the time had predicted the inclement weather as early as July 9th (5 days in advance!) and issued warnings for climbers in the Karakorum for the same July 14-19 period.


Specifically, the Pakistani meteorologists noticed a jet stream disturbance (essentially a middle-latitude storm) coming in from Europe to the west. The disturbance stalled and became stationary just to the west of the Mustagh-Ata/Kashgar region. This upper air disturbance triggered a surface low pressure anomaly centered pretty much right over us. This in turn induced a strong southerly flow of moist air into our region. Surface pressure anomaly maps for this time period show a high pressure anomaly further to the east over China and Southeast Asia. So in essence, this disturbance caused the summertime monsoonal flow to move considerably further west and north of its normal position. Surface wind anomaly maps for the period show this strong southerly flow into the Mustagh Ata region. Upper air wind and height field maps show that this moisture flow was very deep, extending most of the way through the troposphere (weather producing part of the atmosphere). (Because of size considerations, I’m not including any graphics with this write-up, but would be happy to send some maps to anyone who might be interested, or show you where to download them yourselves from the US Climate Diagnostics Center.) Of course even a strong flow of moisture only sets the stage; something has to actually lift this moisture to cause rain or snow. This lift was provided by little ripples, or waves, embedded within the deep southerly flow. Lifting occurs during the front portion of one of these waves, causing the snowfall, while air descends in the back portion, accounting for the partial clearing after a snow event. These waves typically travel through in about 12-18 hours, accounting for the approximately 8 hours of snow followed by about 8 hours of improving conditions.


So that, hopefully in laymen’s terms, is what happened (remember I am a professional meteorologist/climatologist so hopefully I’ve kept the ‘jargon’ to a minimum). The other question on everybody’s mind is how often does an event such as this happen, that is, how unique was it? While still on the mountain, I heard plenty of anecdotal evidence from people with experience in the area that it was pretty rare – comments such as ‘the monsoon never gets here; its blocked by K2’; ‘it never snows here in summer for more than a day or so at a time’; ‘in all my years around here I’ve never seen so much summertime snow’, etc. But of course anecdotal evidence is not scientifically rigorous (‘100’ year storms really happen about every 10 years!). Unfortunately, this is a very remote region of the world that has been little studied, so I was unable to find historical work from which I could base a more quantitative determination of how frequently such an event might occur. (If anyone knows of such a source please let me know!) I did find one compelling, and somewhat disturbing study by a Chinese climatologist named Hu Ruji form the Xinjiang Ecology and Geography Institute, performed under the auspices of the Chinese Academy of Sciences. This study found that over the past 15 years, much of western Xinjiang (west of the Tianshan Mountains) has been shifting from warm and arid to warm and humid. In particular, he has found that runoff and lake levels have increased significantly over this period, with at least one major lake reaching historic record high levels in 2001 and 2002 (the study was published in early 2003). He implies this may be due to ‘greenhouse-gas’-induced global warming. If Ruji’s study holds true, it does suggest that heavy snowfalls in the Mustgah Ata region (recall the summer of 2004 had exceptionally heavy snows even before the big storm) may become more frequent as time goes by!

Side 1 2 3 4 5 Diverse

klik på sidetal for valg af side

Back to mountaineering frontpage

Last update: 26-1-2005

© Hans Bräuner-Osborne