Nepal’s Department of Hydrology and Meteorology (DHM) has issued a special weather bulletin about Cyclone Arnab. The storm is gathering strength over the Bay of Bengal. Its effects are expected to reach Nepal from Thursday night, October 29. This report covers what DHM says, which regions face the most risk, and how to prepare.
This is a fast-moving story. Forecasts can change. So, treat official DHM bulletins as your main guide, and check them before making plans.
What DHM Is Saying
The Weather Forecasting Division under DHM issued its special bulletin on Monday afternoon, October 26. According to the division, Cyclone Arnab is expected to intensify into a severe cyclonic storm. It could then develop into a very severe cyclonic storm.
The system is moving northwest. It is forecast to approach the Yanam coastal area near Visakhapatnam in Andhra Pradesh, India, on October 28.
When Nepal Will Feel It
The division said the system would begin affecting Nepal from Thursday night, October 29 (Kartik 12). Friday and Saturday are expected to bring the most weather activity. Adverse conditions are expected across most of the country from Kartik 12 to 14, which is October 29 to 31.
Cloud cover may start building earlier. Reports note that the system’s influence could begin from October 28. However, the main rain and snow window is Thursday night through Saturday.
Which Provinces Are Most Affected
DHM named five provinces likely to be particularly affected on Friday and Saturday: Koshi, Madhesh, Bagmati, Gandaki, and Lumbini.
- Koshi, Madhesh, Bagmati, and Gandaki: Many places are likely to see light to moderate rain with thunderstorms and strong winds.
- Lumbini: Similar conditions are forecast in parts of the province.
- Karnali and Sudurpashchim: Some areas may see rain and thunderstorms, with heavy rain possible at one or two places.
News reports of the bulletin add that some areas could see moderate to heavy rain with thunder and lightning on October 30 and 31. Parts of Lumbini could see heavy rain.
The Warning for the Mountains
DHM warned of a risk of heavy snowfall, snowstorms, and avalanches in high-hill and Himalayan areas. It advised tourists to avoid high-altitude destinations and to stay in safe locations during this period. DHM has also marked several Himalayan districts in red to show a higher level of risk.
An earlier DHM outlook gave more detail on snow. It said moderate snowfall was likely in mountain areas of Koshi, Bagmati, and Gandaki provinces. Some places could see heavy snow, with very heavy snowfall possible at one or two locations.
Wider Risks Named by DHM
The division also cautioned that rain and snow could cause several problems:
- Lower temperatures and a spell of intense cold
- Floods and landslides
- Road blockages
- Disruptions to air services
It urged the public and relevant authorities to make preparations in advance.
Advice for Farmers
DHM warned that the rain could harm the agricultural sector. It asked farmers to complete farm work, including paddy harvesting, before Thursday. The timing matters because late October is harvest season, and ripening paddy is still in many fields.
Practical Steps for Farmers
- Harvest only what you can dry and store before the rain begins.
- Cover cut crops with tarpaulin or move them indoors.
- Clear drainage around fields to avoid waterlogging.
- Check the forecast every morning, since timing can shift.
Advice for Trekkers and Tourists
DHM’s guidance is direct. Avoid high-altitude destinations and stay in safe places. The risks include blizzards, avalanches, and very poor visibility.
This is not a minor warning. In October 2014, a snowstorm in central Nepal killed at least 43 people, including at least 21 trekkers. At the time, no system warned trekkers about conditions on their route.
What Trekkers Should Do
- Check the DHM forecast before every trekking day.
- Postpone high-altitude treks and pass crossings until the system passes.
- Talk to your guide and agency about waiting or turning back.
- Carry warm layers, food, and a charged phone.
- Tell someone your route and daily plan.
Advice for Highway Travelers and Residents
Heavy rain can trigger landslides and washouts, especially on steep mountain roads. DHM specifically flagged road blockages and possible air service disruptions.
- Avoid night driving during heavy rain.
- Check road conditions with local authorities before long trips.
- Allow extra time, and postpone non-essential travel during the peak window.
- If you live near a river, follow your local disaster management committee’s instructions.
- Keep emergency supplies ready in case of sudden flooding.
Other Forecasts and Estimates
Official DHM bulletins are the main reference. Other analysts have added their own views. These are useful context, not replacements for DHM.
An Independent Meteorologist’s View
Meteorologist Binod Pokharel has warned that some Bagmati areas could receive more than 150 millimeters of rain over four days. He has also flagged dozens of districts as higher risk. On Tuesday, he noted that one global model, the GFS, hinted at a second cyclone forming. That could weaken Arnab and reduce Nepal’s risk. Most other models did not show this. He said the overall picture across seven models still shows a chance of heavy rain. According to Baahrakhari, which reported his analysis, forecasting this system is unusually difficult.
A Trekking Operator’s Estimate
A trekking operator in Parbat published an unofficial estimate of 100 to 200 millimeters of rain in many hill areas and up to 1.5 meters of snow in the high mountains. This is a private estimate, not an official forecast.
Why the Numbers Differ
DHM describes many places as “light to moderate” rain, with heavy rain at some spots. Individual analysts highlight higher totals for particular areas. These views are not necessarily in conflict. Rainfall varies sharply across Nepal’s terrain. A valley may see steady drizzle while a nearby slope gets a downpour.
Lessons From Last Year
Nepal has faced this pattern before. In October 2025, Cyclone Montha made landfall in Andhra Pradesh and then affected Nepal. Authorities issued alerts in 26 districts across three provinces. The Nepal Army reported that hundreds of trekkers heading toward Tilicho Lake had to turn back when snow blocked the trails. Reports also link Montha to a disastrous avalanche in Nepal in November 2025.
The comparison is not exact. Still, it shows that distant cyclones can have real effects in the Himalayas.
What to Watch Next
- Arnab’s landfall and track: Its path after landfall decides how much moisture reaches Nepal.
- Updated DHM bulletins: These will refine which districts face the highest risk.
- District disaster management committees: They announce local road closures and safety measures.
Final Thoughts
DHM’s message is clear. Cyclone Arnab is expected to affect much of Nepal from Thursday night, October 29, with the greatest impact on Friday and Saturday. Rain, thunderstorms, and strong winds may hit the hills and plains. Heavy snow and avalanche risk threaten the high Himalayas. Farmers should finish harvesting before Thursday. Trekkers and tourists should avoid high-altitude areas. If the weather turns milder, little is lost. If it does not, preparation could prevent serious harm. Follow official updates closely.
Frequently Asked Questions
What has DHM said about Cyclone Arnab?
DHM’s special bulletin says Arnab will begin affecting Nepal from Thursday night, October 29, with Friday and Saturday expected to see the most rain, snow, and wind.
Which provinces are most affected?
Koshi, Madhesh, Bagmati, Gandaki, and Lumbini are expected to be particularly affected. Parts of Karnali and Sudurpashchim may also see rain.
Is it safe to trek in the Himalayas right now?
DHM advises tourists to avoid high-altitude destinations during this period because of heavy snowfall, snowstorms, and avalanche risk.
What should farmers do before the rain?
DHM asked farmers to complete harvesting, including paddy, before Thursday. Cover cut crops or move them indoors if rain arrives early.
What other risks did DHM mention?
DHM warned of floods, landslides, road blockages, disruptions to air services, and a drop in temperatures.
Where can I find the latest official updates?
Check the Weather Forecasting Division of the Department of Hydrology and Meteorology, along with district disaster management committees and trusted local news.
