A glacier collapse in Tibet caused catastrophic flash flooding Wednesday in a border area of China and Nepal. Authorities in both countries have reported more than 160 deaths and over 1,300 people missing as of Thursday. Many were foreigners in the area for trekking or a pilgrimage to a sacred Hindu site.

The number of missing may vary across agencies due to differences in how they collected data, when it was reported and how it was verified, as well as gaps in coordination between those assembling data and those conducting rescue efforts in the affected area.

Nepal

Police reported at least 165 dead and 826 missing. Local reports cited the National Emergency Operation Center as saying Thursday the missing included 113 Nepali tourists, 85 security personnel from the army and police as well as 161 residents from the Rasuwa district and one from the Nuwakot district.

The National Tourism Board later Thursda...