Leh Cloudburst: What caused it? The Most Plausible Theory

Many visitors to this blog were referred by Google Search to our recent posting A Swing Away from CO2 Global Warming, A Rebirth of Solar Theories to Climate Change??  due to a reference to the Leh Cloudburst.  Most were searching for a deeper scientific understanding to the phenomenon.  A few days ago, the media was also abuzz with a speculation that the Leh Cloudburst was a result of Climate Change. Both these developments spurred this posting. There are many presumptive theories floating around on the Leh Cloudburst. We attempted to take stock of all these to identify a theory that appears the most plausible. The climatologist fraternity within the country could perhaps build upon the following analysis.

Theory 1: UFO 

The theory states that the event is due to extraterrestrial UFO effects!  There are reports for the last five years that the area and Aksai Chin is the home of underground UFO bases. UFOs with electromagnetic flux overdrive can cause unintended artificial cloudbursts over a short region with very high intensity. To be mystified more, read here.

Comment:  If it were indeed extra-terrestrial, driven then it would be futile to try to give any climatic explanation to the Leh Cloudburst. Nevertheless, what is extremely interesting is that UFO being attributed as a cause only to explain electromagnetic flux that in turn is often intrinsically significant in triggering cloudbursts.

Theory 2: Chinese Weather Experiments

The event was caused by Chinese artificial weather, storm and cloudburst experiments.  Are there such weapons/technology? Yes say some. Read more here.

Comment:  Like in the case of UFO, if it were indeed weapon triggered then it would be futile to try to give any climatic explanation to the Leh Cloudburst.

This speculation arose mainly because Leh is an unusual place for a cloudburst, being a cold desert region where average rainfall is extremely low. Scientists say convective clouds began disgorging its moisture between 1.30am and 2.30 am on August 6th. The Indian Meteorological Department (IMD) estimated that Leh received 48.6 mm rain in one hour. The high-impact event was so localised that that a nearby meteorological observatory of Indian Air Force (IAF) reported only 12.8 mm of rainfall during the full 24 hours.

It is such doubts that fuelled the suspicion that the Leh extreme event could be result of some Chinese weather experiments. The conspiracy theory targeting China is also natural given the Buddhist population and the fact that Leh in ancient times was a part of Greater Ladakh spread over from Kailash Mansarover to Swaat (Dardistan). Both fans pro-Tibet and anti-China sentiments among its population.

Theory 3: Army’s Tree Plantation Programme causes the Cloudburst 

“There was a talk among the Ladakhis that the tree plantation drives there is causing more rainfall every year. We have to understand that Ladakh region is traditionally a rain shadow region the mud houses are bot built for excessive rain. In fact, there was even a campaign of "Ped Kato. Ghar bacho" (Cut trees to save Ladakh).”

Comment: This theory is probably fuelled by huge local resentment against the Army’s insensitive tree planting programme that probably deprived locals of their commons - grazing, fuel wood gathering etc. It has to be kept in mind that traditional culture of Ladakh has been nomadic and it is only recently an agrarian transformation took place. Nomadic instincts may not appreciate the need for nature conservation and besides Ladakhis rear alot of mountain goats. However, the theory’s “scientific” explanation for increasing rainfall lies in attributing it to the changing of a highland desert into a green belt. This may fail the scientific validation test but that's how the local populace perceive this climatic trend.

There is some prima facie evidence however to suggest that though trees by themselves may not have triggered the cloudburst, they may have significantly contributed to the flash flood impact.

  

“Trees and some cultivation in areas along the Indus where land has been encroached upon added to the problem. The growth further restricted the flow of water"

said Minister of State (MoS) in Prime Minister’s Office (PMO), Prithviraj Chavan who was in Leh. The fact is that the charge so rattled the Army that they hurriedly promised to initiate research to contain soil erosion the area.

But the theory also brought out a particular climatic significance of Leh - it lies as a rain shadow area.

Theory 4: It’s all Climate Change

“Based on a detailed analysis of weather data of the last five years in Leh, scientists have attributed the recent cloudburst in the region to prolonged winters which may be due to climate change...

After going through the sequence of events of the weather that led to the cloudburst on August 6, it has been reinforced that the catastrophe was due to prolonged winters being witnessed in the region,” a source at the Leh-based Defence Institute for High Altitude Research (DIHAR) told PTI.

The analysis by the research institute under the Defence Ministry was done to look into the reasons that triggered the cloudburst in the Leh region on Ladakh, which is usually considered unnatural because it is a rain shadow area.
On condition of anonymity, the source said at a recent meeting on “Evaluation of climate change in Ladakh sector and causes of Cloudburst in Leh,” the scientists at DIHAR had analysed the weather data of the last five years in terms of monthly temperature, rainfall, humidity and snowfall. The study indicated that increased temperature and hot summers in the plains lead to increased evaporation and subsequent cloud formation in the hills.

“This in turn, led to increased duration of snowfall in Ladakh when compared to previous years. The winters in Ladakh were found to be prolonged,”

the experts concluded though they felt the phenomenon could not be directly associated with climate change given the short range of data.

The region was witnessing unusual phenomenon of bright sunshine in June and July causing melting of snow and high relative humidity (72 per cent) as compared to previous years (50 per cent), the source said. Tracing the change in weather on the basis of the data available, the source pointed out “since snow absorbed the latent heat also, the monthly maximum and minimum temperature remained low and did not shoot up as compared to previous years (2006).

The low temperature and high relative humidity lead to formation of dense low clouds in the valley. Since the vapour content in the clouds were high and on trying to cross the glaciers, the vapours further condensed.

“The clouds could not retain the water droplets that lead to the cloudburst. Since the rainfall was absent on August 3, 4 and 5 and was negligible on August 7, 8, and 9, the theory of occurrence of a cloudburst in Leh due to prolonged winters may be reinforced,” the meeting said on the sequence of event.” 

Comments:  Except for media reports, no report of such a study can be found on the net or the website of DIHAR who has been attributed as having had conducted such a study.  Moreover, what exactly is DIHAR? They are solely focused in R&D in cold high altitude arid agro animal technologies! It is obvious that they do not have any specific competence in climatology worth the salt nor are they recognized in the country as having one! This may not be any study at all since in the last paragraph mentions these findings as conclusions of  "a meeting”! The media reports besides attribute the findings to “a source” and quotes people “in condition of anonymity” giving credence to the suspicion that this is very much a planted bogus story.

So who would want to plant such a story? Dragging of DIHAR, a defence outfit into the story together with the fact that the army is in the receiving end of public wrath for their tree-planting programme, makes the obvious suspect is the Army themselves. 

However, it could well be the handiwork of the tribe of enviro-journalists. The latter often have one foot within mainstream media, another with environmental organizations such as Greenpeace, pursuing a strong climate change agenda.

This lobby in the country has suffered quick reversals in fortune and it is to this tribe of enviro-journalists they turn for quick fixes. Leh has been particularly a setback with leading climatologists ruling out links to climate change or global warming. Even when climatologists say this in the clearest of terms, these enviro-journalists also manage to confuse their readership by diluting their remarks. See how skilfully Max Martin does with his article Boomtown Rap: Ladakh floods are talk of the town in India Today. He interviews Dr. M Rajeevan, one of the best-known climatologists in the country who in unambiguous terms pronounced a lack of link between Leh cloudburst and climate change. Yet in the very next paragraph, Martin resurrects the whole climate change bogey itself:

“With global warming, it is expected that frequency of extreme weather events will increase” notes Dr M Rajeevan, senior scientist at ISRO's National Atmospheric Research Laboratory in Tirupati. “At many places, including over India, such trends are now observed. Rajeevan, however cautions that though it is easier to speculate, Pakistan and Leh events cannot be clearly attributed to global warming. These events can be explained with (other) physical reasons. Making a one-to-one connection with climate change may be difficult in the case of the cloudburst.

However scientists say it is ironic that the villagers of Leh with possibly one of the smallest carbon foot prints on earth - with their limited consumption patterns - should suffer from the impacts of climate change, whatever they may be."

Leaving aside that this study could be a bogus media plant; it contradicts itself in the first and fourth paragraphs. It first attributes the cloudburst “to prolonged winters which may be due to climate change” while the fourth confesses that “the phenomenon could not be directly associated with climate change given the short range of data.”  Prolong winters are besides indicators of likely of global cooling while “increased evaporation and subsequent cloud formation” are more likely linked to global warming!

The claim that increased temperature and hot summers in the plains lead to increased duration of snowfall in Ladakh when compared to previous years is simply nonsense. The summer of 2009 had been mild in Russia and still the country experienced one of the most severe winters latter in the same year. The La Nina is expected to last through early 2012, accordingly we will be likely to have a milder summer next year, and yet Himalayas can be expected to experience a severe winter later in the year.  

The main drawback of this theory is it falls to give a synoptic analysis of the immediate trigger to the cloudburst.

Theory 5: Heavy Rainfall associated with the annual Asian Monsoon

This is how National Oceanic and Atmospheric Administration (NOAA) attributed the cause of the cloudburst in their State of the Climate Global Hazards August 2010: 

“Heavy rainfall, associated with the annual Asian Monsoon, near Leh, India on August 6th triggered flooding and mudslides which killed 132 people and left another 300 missing. Mudslides buried parts of Choglumsar, which was the worst hit area. More than 400 people were injured in the floods, caused by a cloudburst, which struck without warning in the region. Thousands more were left homeless. Leh lies 11,500 feet (3,500 meters) above sea level and is in a usually arid part of Indian Kashmir where heavy rainfall is uncommon.”

This report also provided the map - Asian Rainfall Anomaly, 1–9 August 2010

Comments: NOAA clearly categorised Leh as a natural disaster associated with the monsoons.  While attributing the cause to a cloudburst, NOAA failed to provide the synoptic analysis. The real contribution of NOAA’s report was the Asian Rainfall Anomaly Map 1–9 August 2010 that clearly establishes that the whole of J&K, including Leh, experienced positive rainfall anomaly. This is in contrast to the climate change theory that attempted to establish Leh’s rainfall as totally a micro-driven phenomenon. 

Theory 6:  Interaction of Westerlies with Monsoon Current

The IMD official report, Cloud Burst over Leh (Jammu & Kashmir) stated the following:

“Analysis of Satellite Imageries indicates that the intense convective system developed in the easterly current associated with monsoon conditions over the region. The convective cloud band extending from southeast to northwest developed over Nepal and adjoining India in the afternoon of 5th. It gradually intensified and moved west-northwestward towards Jammu & Kashmir. An intense convective cloud clusture developed to the east of Leh by 2130 hours IST of 5th August. Satellite Imageries of 0030 hours IST (2100 UTC) to -0600 hours IST (0030 UTC) of 6th August.

The cloudburst was highly localised, as the nearby meteorological observatory of Indian Air Force (IAF) reported 12.8 mm of rainfall during 0530 hrs. IST of 5th to 0530 hrs. IST of 6th August.

According to synoptic analysis, the monsoon trough at the mean sea level lay to the south of its normal position on 4th and 5th August. There was a cyclonic circulation in lower levels over west Rajasthan and neighbourhood. A well-marked low-pressure area lay over northwest Bay of Bengal on 5th and over north Orissa and neighbourhood on 6th August. Under the influence of these systems, strong southeasterly winds with speed of 15-20 knots prevailed over western Himalayan region.

The forecast issued by Meteorological Centre, Srinagar based on 0830 hrs IST observation on 5.8.2010 was as: Rain/thundershowers would occur at a few places with moderate to heavy showers at isolated places in Jammu & Kashmir.

Usually, the western Himalayan region experiences the cloudburst events during the monsoon season in association with the strong monsoon circulation or the interaction of monsoon circulation with the mid-latitude westerly system. The orography of the region plays a dominant role by increasing the convection and hence the intensity of cloud burst. It also occurs over other orographically dominant regions like the northeastern states and Western Ghats region. It can occur also over the plain areas, but the frequency of such occurrence is very rare. However, Laddakh region of J&K is not known to be frequently affected by this type of phenomena. It is a cold desert and average rainfall for the month of August is 15.4 mm only. The highest rainfall ever recorded over Leh during 24 hours period has been 51.3 mm recorded on 22 August, 1933.”

Comment:  We have yet another confirmation. This time from IMD that Leh convective cloud was not a standalone phenomenon, as made out to be by climate change activists; but part of a convective cloud band extending from southeast to northwest developed over Nepal and adjoining India in the afternoon of 5th August and developed over Leh towards the East of Leh by 22.30 hrs IST. There was a strong southeasterly winds with speed of 15-20 knots prevailed over western Himalayan region which probably brought in these convective clouds over Leh.

The synoptic analysis provided was however not very definitive on what could have triggered the cloudburst. It hints however that it could be interaction of (warmer) monsoon circulation with the (cooler) mid-latitude westerly system. IMD speculates that the intensity of the cloudburst could be accounted by orographical conditions. An orographic (terrain-induced) lift occurs when an air mass is forced from a low elevation to a higher elevation as it moves over rising terrain. Studies show narrow barriers and steeper slopes produced stronger updraft speeds, which, in turn, enhanced orographic precipitation.

As the air mass gains altitude it expands and cools adiabatically, which can raise the relative humidity to 100% and create clouds and, under the right conditions, precipitation. Cooling happens as air mass expands with increasing elevation (because density of gases decreases farther into the atmosphere). As elevation increases, the air gets cooler because energy is drawn from the surroundings. Less dense air traps less heat resulting in this net cooling. This is called adiabatic cooling. It occurs at an average of 6 degrees Celsius per 1000 meters, but it can vary.

If enough water vapour condenses into cloud droplets, these droplets may become large enough to fall to the ground as precipitation. Westerlies normally affect the windward side of a mountain than on the leeward side as moisture is removed by orographic precipitation. Drier air is left on the descending, generally warming, leeward side where a rain shadow is formed. The trouble is Leh falls on the rain shadow area and probably why the IMD, though mentioning orographic precipitation as a possibility tends to consider it unlikely as a cause for intensity of the cloudburst. Moreover, Ladakh is an exception for such climatic conditions because of unavailability of widespread water bodies, thick vegetation and cold climate.

Theory 7:  Thunderstorm occurring within an extremely moist & warm environment

 
Dr. Greg Forbes, an extreme weather expert writing in the Weather Channel Blog questioned with such low rainfall intensity, whether the event even could be categorised as a cloudburst:

“I'm not sure of the accuracy of the one-minute rainfall rate, as the official statement by the India Meteorological Department said that rainfall may have been 4 inches per hour. That would be more typical of a slow-moving heavy thunderstorm. Even that rainfall can trigger flash flooding.

However, how hard can it rain from a thunderstorm? The official world record for a one-minute period is 1.23 inches at Unionville, MD on July 4, 1956. That would be nearly 74 inches (over 6 feet) if that rate could have lasted for an hour. The diagram below shows several other official rainfall records, with the unofficial report from today near Leh, India included. Compare those extreme rains with Arica, Chile, which averages only 0.03 inches of rain per year.

How could a thunderstorm produce more than an inch of rain in a minute? It's hard to fathom.

However, it seems likely that it would require a thunderstorm occurring in a very moist, warm environment. The moist, above-freezing layer should extend very high so that there would be a deep layer of accumulating rain rather than a lot of hail. The thunderstorm would need to have a strong updraft to accumulate a lot of rain suspended aloft, as depicted below.

Then, somehow, the updraft should stop and be replaced by a strong downdraft that would drive the rain toward the ground much faster than it would fall naturally, as shown below. That combination is the only one that seems likely to make it rain at such extreme rates.

Comments:  While NOAA did not provide any synoptic analysis for the Leh Cloudburst, they referred this link of the Weather Channel Blog of Dr. Greg Forbes and we can easily see why. Forbes has been very lucid. Nobody knows for sure how much rainfall fell and at what intensity. All we have to go by is what’s given by the IMD and accordingly we can conclude that based on this the cloudburst was those of a slow-moving heavy thunderstorm.  

 
The Challenge Ahead

What Forbes fell short was the explanation what forces actually caused the strong updraft and downdraft? In fact, this is where all theories have failed to explain. If we need to crack the Leh Cloudburst in order to adequately and scientifically explain it, then we must identify what forces were behind both the strong updraft and downdraft.

However, this is the extremely difficult part. There are some many possibilities and more over data is lacking.

The following list of hypothesis provided is just to whet the appetites of future climate researchers who may study the Leh Cloudburst in great depth.

1. The meteorologically assigned cloud type associated with the thunderstorm that could have caused destruction on a scale as witnessed in Leh should be logically the cumulonimbus of the super-celled variety. Only a super cell with a rotating updraft can produce extreme severe weather events such as those attributed to the Leh Cloudburst. Winds need to come from different directions to cause the rotation.

Moreover, as precipitation is produced in the updraft, the strong upper-level winds blow the precipitation downwind. Hardly any precipitation falls back down through the updraft, so the storm can survive for long periods. However, since the storm survived merely one hour, does it rule out a super-cell and increased the probability of it being only a multi-cell cluster storm?

2. Given the total rainfall, the cloudburst per se held little by way of disaster potential. Can it be ground conditions, natural or manmade (like tree plantations), that accentuated the flash flood impact of the Leh Cloudburst?

3. As per a 2005 report in International Association for Ladakh Studies, Leh holds very high potential for generation of geo-thermal energy lying on the zone of collision between the Indian and the Eurasian plate. Could the trigger for uplift include heating by geo-thermals? Could these also explain why rivers in Leh have been running at alarming levels?

4. Adiabatic heating and cooling is common in convective atmospheric currents. Adiabatic changes in temperature can also occur due to changes in pressure of a gas while not adding or subtracting any heat. Since pressure can also be affected by strong electro-magnetic flux, adiabatic heating or cooling consequently could be affected by the later. Coronal mass ejections (CME) also trigger electromagnetic disturbances on the Earth.  The last CME reached earth just 24 hours before the Leh Cloudburst. Could this have triggered either the updraft or downdraft of the tropical storm?

 5. Westerlies are part of the jet stream, flowing from west to east. The period mid July to mid August, showed the jet stream demonstrating a kink where it split up into two branches - one deviating from its normal path in the North and another going South to Pakistan. Monsoon rains drive air upward, and that air has to come down somewhere. It usually comes down over the Mediterranean, producing the region’s hot, dry climate. This year, due to jet stream blockages, some of that air seems to have gone north to Russia. Meanwhile, the Siberian cold air usually goes rest over Russia and East Europe, moderating summer temperatures. This time it was blocked and had to go somewhere. This year some of it went to South Asia. The result was heatwaves in Eastern Europe (Russia) and floods in South Asia (Pakistan).

Damodar S. Pai, Director, Forecast, IMD, who closely following Asian weather patterns from his Pune office told Hindustan Times that the torrential rains in Pakistan could have easily occurred in India had the storm built up a few hundred miles away on the Indian side. In the case of Leh, this would be much closer. Very much closer. Could it be this jet stream anomaly be linked to the cloudburst as it can be easily triggered by inflow of cool air from Siberia clashing the warm moist thunderstorm?