A quick reminder

There have been two memorable instances of severe flooding in Uttarakhand in recent years. In February, a catastrophic flood triggered by an avalanche killed 200 people and destroyed two under-construction dams (explained here). The greater tragedy occurred back in 2013 when 6000 died in a torrential downpour caused by a ‘cloudburst’. What happened yesterday is similar to the events of 2013.

Tell me about the floods…

The magnitude: The rains in Uttarakhand broke all records. Ten districts have recorded between 100 and 500 millimetres (mm) of rainfall in three days. Champawat in the Kumaon region recorded 579 mm within just 22 hours. The water level in the Ganga in Haridwar has reached 293.90 metres, just a notch below the danger mark of 294 metres. Naini Lake in Nainital city overflowed, flooding roads and homes. According to one survivor:

“I can never forget the mental picture in my life. It was the first time that I saw so much water on the streets of Nainital. The water from Naini was gushing through the streets in a torrent.”

Nainital looked like this:

And this:

The death toll: currently stands at 47—with 42 deaths occurring just on Tuesday. The greatest number—28—died in Nainital district. 

OTOH: In the midst of this horror, the yatra to Yamunotri in Uttarkashi has resumed with a record 2,381 pilgrims visiting the temple on Tuesday—even though the Chief Minister asked them to shelter in place.

The immediate cause: There have been two low-pressure systems active over the Arabian Sea and the Bay of Bengal—the latter is responsible for the heavy rains in Uttarakhand. The other reason: An active “western disturbance.” North India experiences this phenomenon in the winter season—when areas of “disturbed air pressure” travel to India from the west, carrying moisture all the way from the Atlantic Ocean. These most often cause early snowfall.

The silver lining: According to the weather forecast, the rains will recede this week.

How is climate change a factor?

There are several ways in which rising temperatures dramatically affect weather patterns—and it's happening across India.

Extreme weather: As we’ve explained before, this entire monsoon season has followed a stretched out start-stop-pour pattern. And it matches climate change predictions for India: extended monsoon with long dry stretches interspersed with bouts of torrential rain. These extreme events have become increasingly common in Uttarakhand. It has reported over 7,750 extreme rainfall events since 2015—most of them in the last three years. As of July, there have been 979 such instances—which may be an underestimate since many areas do not have a weather station. 

About those cloudbursts: A cloudburst is defined as rainfall of over 100mm/hour within a limited geographical area of a few square kilometres. And here’s how they form: 

“[M]oisture-rich air travels up a mountainous region, forming a vertical column of clouds known as Cumulonimbus clouds. These clouds usually cause rain, thunder and lightning. This upward movement of clouds is also known as ‘orographic lift’. Due to these unstable clouds, heavy rainfall may occur over a small area.”

In the case of Uttarakhand, these cloudbursts are often triggered by rising temperatures in the Indian Ocean—which is, of course, a result of global warming. The 2013 floods were a result of a cloudburst. Between June 13 and 19, the state received excess rainfall of nearly 850%!

Rising temperatures: A recent study predicts that Uttarakhand will be 1.6°C-1.9°C warmer by 2050. And it shows that districts at higher elevations are heating up fastest. The link between rising temperatures and cloudbursts in the Himalayas is still not entirely clear. According to one Indian geologist:

“The Himalayas are witnessing less snow compared to the past but simultaneously rainfall is ascending higher into the Himalayas. When more rain meets steep terrain, it results in higher precipitation and quicker funneling of water downstream, which creates flash floods and flooding in general.”

An indirect effect? What we do know: hotter temperatures lead to melting glaciers—which too will cause catastrophic flooding. The February floods were caused by the collapse of a wedge of glacier-covered rock more than 500m wide and 180m thick. The avalanche was not directly linked to climate change, but experts noted that shrinking glaciers uncover and destabilise mountain flanks—weakening the underlying rock.

Point to note: The severity of the damage caused by these unusual weather events is a result of out-of-control development of roads, hotels, shops and housing in ecologically fragile areas. But the biggest factor: mushrooming hydroelectricity dams—which have proven lethal over and again. As one environmentalist notes:

“There are human factors which are aggravating the human loss in such events. We are cutting trees for development projects, we are cutting hills and destabilising slopes by cutting hills for roads, we have built hydel power projects in fragile Himalayan valleys, we are mining river beds discriminately.”

The bottomline: It’s important to remember that our natural disasters occur for the most unnatural of reasons.

Reading list

Hindustan Times has the best reporting on the floods. Down To Earth looks at the increasing frequency of cloudbursts. Scroll has a good read on how rising temperatures in Uttarakhand are affecting agriculture and migration patterns. BBC News has the best reporting on the causes of the February floods. Also read: Scientific American on the threat of melting glaciers in the Himalayas. These older Mongabay and New York Times articles are the best on the effects of unrestrained development. Also worth revisiting: Our explainer on the February floods which has a lot more on the lethal combination of glacier melt and way too many dams.