Kori La: Driving the treacherous Bumthang-Ura Highway in Bhutan
Kori La is a high-mountain pass that serves as a critical yet exhausting link in eastern Bhutan. Reaching an elevation of 2,406m (7,893ft) above sea level in the Mongar District, the road through the pass—part of the Bumthang-Ura Highway (PNH1)—is a test of endurance. While officially paved, the reality of the surface is a mix of broken asphalt and gravel sections that have deteriorated significantly since its construction in the 1990s.
| Road facts: Kori La | |
|---|---|
| Location | Mongar District, Bhutan (Road PNH1) |
| Max Elevation | 2,406m (7,893ft) |
| Length | 256 km (159 miles) |
| Surface | Paved in poor condition / Gravel patches |
How is the road surface on the Bumthang-Ura Highway to Kori La?
The 256-kilometer journey between Chamkhar and Trashigang is defined by the poor state of the PNH1 highway. The asphalt is plagued by deep potholes and sections where the surface has completely vanished, leaving only a bed of loose stones. This requires a high-clearance vehicle and constant attention to the road to avoid damaging the car's undercarriage. The ferro here is the unrelenting sequence of hairpin bends that snake through the steep terrain. These turns are exceptionally narrow, often forcing larger vehicles to perform wide maneuvers that can be dangerous given the lack of safety barriers and the vertical exposure of the Black Mountains.
Why is the mist a constant hazard at Kori La?
One of the most persistent dangers at the summit of Kori La is the heavy mist that engulfs the pass most of the time. This "white-out" condition can reduce visibility to less than five meters in seconds, turning the narrow road into a blind drive. Without clear sightlines, navigating the hundreds of hairpins becomes a high-risk task where you must rely on slow speeds and the vehicle's lights. The moisture from the mist also settles on the broken asphalt, making the steep ramps and sharp corners unexpectedly slick, especially in the shaded forest sections where the road never truly dries out.
Is the road to Kori La passable during the winter?
Located in the southeastern-central Himalayas, Kori La is vulnerable to heavy snowfall during the peak of winter. While the pass is generally maintained, it is common for the road to be closed for 24 to 48 hours following a major storm. Even when open, the high-altitude environment means that ice remains a threat in the shadows long after the snow has been cleared. Curiously, from early April and May, snow is rarely seen at this elevation, but the spring thaw can lead to minor landslides that block parts of the narrow highway with rocks and mud, requiring drivers to stay alert for fresh debris on the driving line.
What are the logistical challenges of driving through Kori La?
Crossing the Kori La is a slow-motion journey through a remote and wild landscape. The road passes through dense rhododendron forests where the narrowness of the path is compounded by the presence of local wildlife and steep rock walls. Because of the 256km length and the technical nature of the driving, this is a multi-hour trip that demands full mechanical confidence. Fuel stations are sparse between the major districts, and a breakdown in these mountains is a logistical nightmare. Ensuring your steering and braking systems are in perfect condition before leaving Chamkhar is not just a recommendation—it is a mandatory safety protocol for the Bhutanese interior.