Who is missing? Planning for people passing through high-risk corridors

Following the Nepal-China border flood, thousands remained unaccounted for.

What stopped me was a police notice asking relatives overseas to send DNA profiles back to Nepal. It made me realize that after a cross-border disaster, responders may face two searches at once: Where are the missing, and who was actually there?

After the August 26, 2026 flood along the Nepal-China border, many of those still unaccounted for were not residents of the valleys where they disappeared. They included pilgrims, tourists, workers and other travellers moving through an international corridor. I had already been thinking about how mobility changes exposure in mountain regions. The aftermath showed me another side: when people move through risk, the information needed to account for them can be scattered across borders too.

Knowing who was present also matters for measuring disaster losses. Under Target A of the Sendai Framework, countries monitor disaster-related deaths and missing persons, so accurate information on who was in an affected area can help establish these losses.

Who was actually there?

Preparedness usually begins with places: settlements, roads, hospitals, evacuation routes and the number of people who live inside a hazard zone. But border crossings, pilgrimage routes and work sites can hold very different populations from one day to the next.

A traveller may appear in immigration records, hotel booking, a tour manifest or an employer list, but not in local population data. What struck me is that a person can be documented several times and still be hard to account for in an emergency, because no single system holds the whole journey. Local counts can tell responders who lives in a place. They do not always tell them who was there when the hazard struck.

That fragmentation is visible in Nepal’s own missing-person records. On September 21, 2026, the National Disaster Risk Reduction and Management Authority began reconciling reports after finding that some people had been registered as missing both in their home districts and again in flood-hit Rasuwa or Nuwakot. District offices were asked to verify the records, remove duplicates and enter confirmed information into the Setu system.

Identification starts before forensics

Nepal Police has asked relatives living abroad to obtain DNA profiles in the countries where they live and send them, together with INTERPOL (International Criminal Police Organization) missing-person forms, to Nepal for comparison with recovered remains.

Canada has also deployed two Royal Canadian Mounted Police (RCMP) Disaster Victim Identification (DVI) specialists to Kathmandu. In Canada, relatives of missing Canadians are providing DNA samples so familial profiles can be used for comparison.

This is careful and necessary work.  INTERPOL’s DVI process compares post-mortem information such as fingerprints, dental records and DNA with ante-mortem information about a missing person. Visual recognition alone is often not enough.

DNA can help answer “Who is this?” But the process becomes harder when responders do not yet know who may have been present. INTERPOL distinguishes between “closed” disasters, where a list of people involved is likely to exist, such as an aircraft passenger list, and “open” disasters, where the number and identity of victims may initially be unknown. A busy international corridor can contain elements of both.

Plan the information flow before the next emergency

As of September 16 2026, about 5,200 people were still unaccounted for in Nepal, including 636 foreigners. Nepal’s Ministry of Foreign Affairs cautioned that the figures were still being updated as search and verification continued. Families have searched hospitals, provided DNA samples and waited for information that can be difficult to assemble across jurisdictions.

This should be treated as part of preparedness, not as an administrative problem to improvise after the event.

That does not mean permanently tracking everyone who travels through a hazardous region. The privacy risks would be obvious. It means deciding in advance what limited information can be shared, by whom, for how long and under what emergency conditions.

Tour operators and major employers could keep current manifests during periods of elevated risk. Border agencies could establish protocols for giving authorized response teams limited access to recent crossing information. Countries sharing the same hazard corridor could designate points of contact for exchanging missing-person and forensic information, with clear rules for access, retention and deletion.

The current response offers an example of what this kind of cross-border coordination can look like in practice: Canada is collecting familial DNA through INTERPOL Ottawa and has sent DVI specialists to Nepal, while Nepal Police is receiving DNA profiles and INTERPOL forms from relatives living abroad .

None of this would stop a flood. It could reduce the information vacuum that follows one.

Mobility changes recovery too

A person may cross one border on a passport, travel with a group organized in another country, carry a phone registered somewhere else and have close relatives living on another continent. Modern travel makes that ordinary. Disaster-response systems are often organized around  national authorities, even when disasters and the people affected by them cross borders.

The response from Canada mentioned above, shows how many systems may have to connect. Following a missing person through this process can therefore involve relatives, police, forensic specialists, border authorities and international organizations, with information moving between countries and across different systems.

That mismatch matters beyond identification. Accurate disaster records depend on knowing who was exposed, who survived, who remains missing and who died. Families may struggle to begin legal and administrative processes while a relative’s status is unresolved. Future risk assessments are also weaker when transient populations disappear from the record.

In Nepal, some families of the missing have sought official declarations of death so they can proceed with legal and religious processes. At the system level, UNDRR’s disaster-statistics framework says exposure data provide baseline information for risk assessment, planning and prevention .

I started by thinking about mobility as an exposure problem: more people entering a valley can change the consequences of a hazard even when the hazard itself has not changed. The aftermath has made me see mobility as an information problem too.

If people can cross borders easily, the information needed to find and identify them after a disaster has to be able to cross borders too — deliberately, quickly and with safeguards already in place.

Sophia Moxuan Zhang is a Grade 12 student and paleoclimate researcher based in Edmonton, Canada. Her recent first-author research on East Asian monsoon variability was published in Palaeogeography, Palaeoclimatology, Palaeoecology. She has also written about Himalayan disaster risk for the Edmonton Journal.