Every monsoon, the same story repeats on National Highway 10: a landslide near Sevoke or a slope failure on the Bardang stretch cuts the road between Siliguri and Sikkim, sometimes for a few hours, sometimes for days. Through June, July and into August 2026, stretches of NH10 near Sevoke and the 20th Mile Bardang section have seen repeated closures, with traffic diverted onto alternate routes while restoration work continues. If you’re shipping goods to Siliguri, Gangtok or anywhere in the hills during monsoon, this is worth planning around rather than being surprised by.
Why NH10 Is Vulnerable Every Monsoon
NH10 runs along the Teesta valley for a large part of its length between Sevoke (near Siliguri) and Sikkim, cut into steep, geologically young hill slopes that were never especially stable. Heavy monsoon rainfall from June through September saturates these slopes, and cutting + widening work on the highway over the years has left several stretches — Sevoke, Reang, Rambi Bazar, and the 20th Mile Bardang section closer to Rangpo — prone to slides, boulder-fall and road cave-ins. This isn’t a one-off event; it’s a near-annual pattern that repeats with varying severity depending on how heavy the rains are in a given season.
When a slide blocks the main carriageway, traffic is usually diverted through alternate roads — commonly via Coronation Bridge–Mongpong–Gajoldoba, or the Melli–Kalimpong side routes, or the Sawhney–Chewribotay–Duga–Rangpo diversion for the Sikkim side. These alternates keep goods moving, but they add distance, add time, and are themselves narrower roads that can get congested once they’re carrying diverted traffic.
What This Means for Your Shipment Timing
The practical effect for anyone booking freight to Siliguri or on to Gangtok and Sikkim during monsoon is simple: build in buffer time. A normal-conditions transit can stretch by a day or more when a diversion is in effect, and if a slide happens to close the road entirely while your truck is en route, it may have to wait it out or backtrack to an alternate. This is true whether you’re moving a full truck load or a part load — the road doesn’t care about consignment size.
- Avoid booking monsoon shipments against a hard, non-negotiable delivery deadline where possible — build in 1–2 extra days of slack.
- For genuinely time-critical or fragile consignments (medical supplies, perishables), flag this to your transporter at booking time so they can plan the route and loading accordingly.
- Keep your consignee informed that monsoon transit times are inherently less predictable than dry-season transit — it manages expectations on both ends.
- Ask your transporter for the current road status before dispatch rather than assuming last week’s route is still open — conditions on NH10 can change within days.
How an Established Siliguri-Based Transporter Helps
This is one of the clearer arguments for booking with a transporter that actually has a branch office on the ground in Siliguri, rather than one coordinating the corridor purely from a distance. Our Siliguri branch office sits on the 2nd Mile, Sevoke Road — close enough to the corridor to track road status directly and adjust routing without waiting on second-hand updates. We’ve been running this corridor since 1985, so our drivers and staff have been through more monsoon seasons on NH10 than most, and know the alternate routes without needing to look them up mid-journey.
None of this means monsoon shipping is risk-free — no transporter can control a landslide — but it does mean fewer surprises and faster rerouting when the road does close. If your goods are also headed onward to Bhutan via the Jaigaon border or further into Assam and the North-East, the same local-knowledge advantage applies on those legs too.
A Quick Monsoon Shipping Checklist
- Build 1–2 days of buffer into your expected delivery window for June–September bookings on this corridor.
- Confirm current NH10 road status with your transporter before finalising a dispatch date, not after.
- Ensure fragile, moisture-sensitive or medical goods are packed for a potentially longer, bumpier transit — see our pharma supplies transport case study for how this looks in practice.
- Keep your consignee’s contact details current so they can be updated directly if a diversion adds time.
- Where the deadline truly can’t slip, discuss dispatch timing with your transporter well before the monsoon peak (July–August) rather than during it.
Have a shipment planned for the Siliguri or Sikkim hills this monsoon and want a read on current road conditions before you book? Call +91 98742 42482 or message us on WhatsApp — we’re happy to talk through timing even before you’ve finalised the booking.
Frequently Asked Questions
Does NH10 close completely every monsoon?
Not every day, but partial or full closures at vulnerable stretches like Sevoke and the Bardang section near Rangpo are a recurring feature of the June–September monsoon on this corridor, with severity varying by how heavy the rainfall is in a given year.
Are there alternate routes when NH10 is blocked?
Yes. Authorities typically open diversions such as the Coronation Bridge–Mongpong–Gajoldoba route or the Sawhney–Chewribotay–Duga–Rangpo road on the Sikkim side. These keep goods moving but usually add travel time compared with the main NH10 carriageway.
How much extra time should I plan for monsoon shipments to Siliguri or Sikkim?
As a general planning buffer, add a day or two beyond your normal-season expectation for this corridor, and treat any hard deadline as something to discuss with your transporter in advance rather than assume.
Does monsoon disruption affect Bhutan-bound shipments too?
If the route to the Jaigaon border passes through an affected stretch, yes — the domestic leg is subject to the same road conditions as any other shipment on this corridor. Building in buffer time is worth doing for Bhutan-bound loads during peak monsoon as well.
Should I avoid shipping to the hills entirely during monsoon?
Not necessarily — goods move on this corridor throughout monsoon every year. The practical approach is realistic scheduling, checking current road status before dispatch, and packing appropriately for a potentially longer transit, rather than avoiding the season altogether.
