China says the Purepu Tsangpo barrier lake has shrunk by 21,000 square metres

China's Ministry of Water Resources said Saturday that the barrier lake on the Purepu Tsangpo, at the China-Nepal confluence where two rivers meet, measured 99,000 square metres in early-morning satellite images. That is 21,000 square metres smaller than Thursday's read, a drop CCTV described as water moving slowly through the debris dam rather than a sudden breach.

Ninety-nine thousand square metres is about 14 football pitches. The ministry's message is that the immediate burst risk at this lake has eased. It is not a statement that the valley is safe.

The second lake is larger

An engineer quoted in the same cycle said another lake, sitting below the glacier collapse, still covered more than 120,000 square metres. Reuters and Al Jazeera have described two bodies of water: a high pond of melt behind ice and rock, and a lower, more dangerous barrier lake where a landslide dammed the river on the Lhende system, near the Chhochen Khola and Purepu Tsangpo confluence, upstream of Gyirong port and the Bhotekoshi-Trishuli chain that runs toward central Nepal.

On Thursday the ministry put water in the barrier lake at 1.5 to 2 million cubic metres and warned that about 3 million more, roughly 1,200 Olympic pools, could flow in over three days, with peak inflow around 1 September. By Friday noon Chinese media said the stored volume had topped 2.5 million cubic metres and that the risk was “manageable” enough for paused rescue work to restart. A military drone on Friday morning also filmed an avalanche that dropped an estimated 50,000 cubic metres of ice into the lake.

Why a shrinking surface is not the end of the file

Barrier lakes fail in two ways. Water can cut a channel and drain, which is the Saturday satellite story. Or the dam can give way in a pulse, which is the event rescue teams still plan against. Rain is forecast through the week. Fresh ice and mud can raise the dam or block the new outlet again.

Gyirong port, the main road link from Tibet into Nepal, was already stripped on Wednesday. A second pulse would hit crews working in a narrow valley with limited helicopter windows. Nepal halted some searches on Friday when river levels jumped. China had done the same until its Friday-afternoon assessment.

The Chinese count

Xinhua on Saturday put the Chinese death toll at seven and the missing at 554, a shift from Friday's CCTV figures of five dead and 558 missing. Access on the Tibetan side remains tightly held. Independent counts are not available.

The useful operational fact for teams in Rasuwa and for Indian units now on the ground is the pair of numbers: 99,000 square metres and falling on one lake, more than 120,000 still standing on the other. The first number lowered the alarm. The second is why the alarm has not been switched off.