Nepal suffers another winter drought

In December, forecasters predicted that Nepal would receive more rain than the three decade average rainfall this winter. We are halfway through winter, and many parts of the country have not received a single drop of rain for four months.

Terrace fields in the mountains are dry, and in the plains winter wheat is drying up. Many Himalayan mountains are naked and snowless. 

“Mukut Himal and many mountains are just bare rock when they should be white with new snow this time of year,” says Madan Sigdel of Tribhuvan University who returned from Upper Dolpo district last week.

Nepal receives an average of 60mm of rain during the three coldest months. However, the Department of Hydrology and Meteorology has recorded just 1.9mm of rain so far this winter. So far, at least, the forecasters have been dead wrong. The 2023-24 winter is turning out to be driest in recent years. 

Bibhuti Pokharel of the Department of Hydrology and Meteorology says that it is too early to declare his office’s weather models wrong. He adds, “Ours was a long-term forecast, it may not have rained yet, but it might rain more than the average during the remaining one-and-a-half months of winter.” 

Indeed, extreme weather events induced by the climate crisis may not see a change in seasonal precipitation totals, but the rain or snow may fall all at once with destructive force. 

Winter weather systems in Nepal are dominated by westerly fronts riding the jetstream that travel all the way from the Mediterranean, passing through Iran, Afghanistan and Pakistan. However, in recent years, the moisture is mostly spent by the time the westerlies reach Nepal. 

“Studies have shown that the increase in sea surface temperature in the Mediterranean has made the whole region warmer and drier,” explains Binod Pokharel, another hydrology and meteorology professor at Tribhuvan University. “This has meant that the winter wind from the west carries less moisture.”

Climate is also greatly influenced by the El Niño and La Niña systems that develop in the Pacific Ocean. El Niño occurs when there are above-average sea surface temperatures in the central and eastern tropical Pacific Ocean while cooling of the ocean there triggers the La Niña. The two events occur every two to seven years, on average. 

During the La Niña phenomenon, cooler sea surface temperatures in the Pacific change wind patterns, disrupting the westerlies and leading to less rainfall. Last winter the La Niña system was active when there was no rainfall in Nepal. 

However, the El Niño system replaced La Niña during the first half of 2023, and the Department of Meteorology has estimated that the El Niño system in the Pacific Ocean will persist right through this winter. Nepal has previously had more rain than average when the El Niño system was active.

An active El Niño system means there will be more than average rainfall, confirms Sudarshan Humagain of the Meteorology Department. “However, it must be noted that in some years, there has been less than average rain when El Niño is active,” he adds. 

What this means is that with climate change, weather patterns have become so unpredictable that most long-term forecasts tend to be inaccurate.  

Indeed, even with an active El Niño, winter rain-bearing westerlies have not been as active as before in Nepal.

Periods without rainfall are classified as drought when the total rainfall is less than 75% of the annual average. The trend so far indicates that Nepal is heading for another winter drought, with a significant part of the country not having had rainfall since October. 

Last year's winter was similarly dry with just 12.9mm of rain, the lowest precipitation recorded in the last 15 years. 

Data shows that 12 out of the last 18 winters had less than average rainfall, and eight out of those 12 winters had droughts. The trend is that winter rainfall is pushed towards the end of the season, and then it falls all at once. 

About 80% of the annual rainfall in Nepal occurs during the monsoon months from June to September, and winter generally sees only up to 4% of average yearly rain.

“This means that two or three instances of heavy rain are normal for winter months,” says Humagain of the Meteorology Department. 

The 2023 Synthesis Report by the United Nations Intergovernmental Panel on Climate Change (IPCC) pointed out that Asia would experience the effects of extreme rainfall variability and drought in the short term as well as long term. The report also noted that winter temperatures are going up across South Asia and 2023 was the hottest year on record. 

“It is certain that winter rainfall is declining while winter temperatures are increasing,” explains Professor Pokharel at Tribhuvan University. “Globally, there has been a trend towards more intense rainfall in the monsoon and falling winter precipitation, and this trend could be the norm in coming years. 

The lack of winter rain and the fact that it is still too early for the winter thaw means that Nepal’s rivers are all running low. This means the country’s total hydropower generation capacity has dropped by 20%, and the shortfall has to be met by power imports from India.

At present, Nepal consumes 1,305MW of electricity on average per day, and nearly one-fourth of it is being imported from India this winter. The figure is higher for morning and evening peak hours.

“Power generation has declined drastically, and is expected to go down further as chances of rainfall look slim,” says Prakash Chandra Dulal of the Independent Power Producers' Association, Nepal (IPPAN) “The output of private sector projects usually drops by to 25-28% in winter.”

The reason is that all private power plants are run of the river type and not reservoirs that would store monsoon rainfall. Nepal has only one reservoir project, Kulekhani which was built in 1984. The second one is finally under construction on the Seti River in Tanahu. 

Generating more electricity in winter is more profitable to hydropower producers because the state-run utility Nepal Electricity Authority (NEA)  buys the power for almost twice the price per unit in winter compared to the monsoon standard rate. 

“The lack of rainfall and decreased river flow costs us around Rs4 million per megawatt,” says Sura Prasad Adhikari of Barahi Hydro Limited. 

Even with imports from India, Nepal’s industries are suffering from power cuts. 

Farmers across Nepal also rely on winter rain more than they do on irrigation systems. Ravi Kiran Adhikari of the Department of Agriculture says that the production of wheat, barley, mustard, lentils, citrus and vegetables is significantly reduced because of winter drought.

“There is still time for the crops to revive if it rains during the remaining months of the winter,” says Adhikari, “But if there is no rain, then our crop output will be seriously affected.”

Meanwhile, lack of rain in winter increases the chance of wildfire as happened in the winter of 2021-22 when the Air Quality Index in Kathmandu soared to record-breaking 700. 

As it is, air pollution in Nepal gets worse during winter months in the Tarai and Kathmandu because of temperature inversion and industrial pollutants from north India. 

This year’s winter drought is already sparking wildfires, with 48 major fires detected by the NASA FIRMS satellite in the past week.