OLDOINYO LENGAI
Welcome to Oldoinyo Lengai
Mount Oldoinyo Lengai (also spelled Ol Doinyo Lengai), known as the “Mountain of God” in the Maasai language, is an active stratovolcano in northern Tanzania, south of Lake Natron near the East African Rift. Rising to about 2,962 meters (9,718 ft), it is Tanzania’s only officially active volcano and one of the most unique on Earth.
It formed over hundreds of thousands of years through rift-related volcanism, with major cone-building phases and collapses. The Maasai revere it as a sacred site associated with their god Engai. Eruptions have been recorded since the late 19th century, with notable activity in 1966–67, 1983–93, 2007–08 (which significantly altered the crater), and ongoing intermittent activity into recent
Weather and Climate
The area around Oldoinyo Lengai is hot, arid savannah with low rainfall overall. Lower slopes experience high daytime temperatures (often exceeding 30–35°C / 86–95°F), making the climb extremely demanding in the sun. Higher elevations are cooler but can still be harsh with strong winds and sudden weather shifts. Nights are colder, especially near the summit. The volcano’s ash and loose material create dusty or slippery conditions depending on recent rain or activity
Climbing Routes
There is essentially one main route, a steep, strenuous ascent (often called the western or standard trail) starting from the base near Lake Natron (around 1,000 m / 3,280 ft elevation). It covers roughly 10–11 km round-trip with over 1,900 m (6,200+ ft) of gain, typically done as a long day hike or with a 2–3 day itinerary including travel.
Climbs usually begin around midnight or 1 AM to reach the summit for sunrise and avoid daytime heat. The trail is relentlessly steep (often 30–45° slopes of ash, scree, and lava), requiring scrambling near the top. Climbers reach the crater rim to view the active northern crater with its natrocarbonatite features. Descent follows the same route and can be fast but loose and tiring. Guides (often local Maasai) are essential due to the volcano’s activity and terrain.
Note: This is a very challenging, non-technical but physically demanding climb — not suitable for beginners. Current volcanic activity must be monitored closely for safety
Interesting facts about Oldoinyo lengai
- It is the only volcano on Earth that erupts natrocarbonatite lava (highly fluid, sodium- and potassium-rich carbonate lava). This “cold” lava flows at 500–600°C (much cooler than typical basaltic lava at ~1,100°C), resembles black oil or mud when fresh, and turns bright white upon cooling and reacting with moisture.
- The lava is among the most fluid in the world (viscosity like water or motor oil) and can move very quickly.
- Deeply spiritual to the Maasai people, who use it for prayers and rituals; its ash fertilizes surrounding soils for grazing.
- Features two craters the northern one is typically active with hornitos (small lava cones), lava lakes, and spattering. Explosive phases alternate with effusive ones.
- Major 2007–2008 eruptions dramatically changed the summit crater and deposited ash widely.
- Provides rare insights into carbonatite volcanism and is studied for its unusual magma composition, which may relate to rare earth elements
Best Time to Climb
The dry seasons are strongly recommended for safer, more stable trails and better visibility:
- June to October — Primary dry season; cooler and more comfortable.
- December to February/early March — Shorter dry period; also favorable.
Avoid the long rains (March–May) when slopes become muddy and slippery, increasing risks. Even in dry periods, start early to beat the heat