Reading Landslide Season on the Tribhuvan Highway
06 Aug 2026 · 2 min read
What changes on the older Kathmandu–Birgunj route once the rains start.
The Tribhuvan Highway, the older route between Kathmandu and the Tarai toward Birgunj which began in 1961, carries a different landslide risk profile than the busier Prithvi Highway, largely because it sees less traffic and, in places, less maintenance. Sections through the hill districts on this route can go longer between repairs after monsoon damage than the more heavily used alternative.
Once the rains start, the road surface itself changes character in ways that catch riders used to the dry-season version of the same route off guard. Sections that were firm, graded dirt in winter turn to soft mud that grips one moment and slides the next, particularly on the steeper descents where water has nowhere to drain except across the road itself.
Because this route is quieter, help is further away if something goes wrong. A breakdown or a fall on the Prithvi Highway usually means flagging down the next vehicle within minutes. On the Tribhuvan Highway in monsoon, that wait can be considerably longer, which changes the calculation on how much risk is reasonable to take on any given stretch.
If you're choosing between the two routes specifically during monsoon, weigh the Tribhuvan Highway's quieter roads against its slower emergency response and less consistent maintenance. For most riders without a specific reason to prefer the older route, the Prithvi Highway is the more forgiving monsoon choice — but if you do take the Tribhuvan, build in the extra caution this section describes.
