August 21, 1986 Tsunami: Lake Nyos, Cameroon

Reference #3402:

[...] a 'bubble' of about 3 million m3 of carbon dioxide came from the depths of the lake to the surface. "A wave of water was sent crashing across the lake reaching an average height of about 25 m along the southern shore and overtopping a 75 m high promontory" (Freeth, 1988).

Reference #13041:

Survivors from the valley recalled hearing a rumble that lasted about 20 seconds and seeing a fountain of water and foam that rose about 90m above the lake’s surface. A wave at least 24m tall scoured the rocky lake shore (Brown, 2000).

Reference #13036:

At the time of our visit the areas where the vegetation had been flattened by a wave of water were still clear. To the south of the lake and in the small cove immediately to the east of the spillway a wave had risen to a height of about 25 m. To the east and north-east of the lake there was little evidence of wave damage. The rock wall to the west of the lake showed evidence of recent rock falls and a significant volume of water swept over the 75-m-high promontory at the southern end of the rock wall [...] However, only about 10 m to the west of the spillway, where the bank is about 2 m above lake level, the vegetation was slightly flattened, suggesting that a small amount of water had slopped over [...] A wave from the north-east could have been reflected and concentrated by the rock wall to the west of the lake in such a way as to overtop the 75-m-high promontory to the south-west. It would also have swept south over the delta plain and into the valleys beyond. A wave originating close to the centre of the volcano which blocks the valley to the north-east is consistent with all the observed damage.

Reference #13038:

Another witness observed a large surge of water wash onto a small peninsula on the S side of the lake, and F. LeGuern later measured its height at 80 m above the lake. Along the E shore the surge height reached [~6] m and water had overflowed the natural spillway to the N by [~4] m.

Note: references #13041 & #13037 suggest max runup of ~25 m while a 90 m height from a "fountain of water" not tsunami runup, while references #3402, #13036 & #13038 suggest ~75 m max tsunami runup.