North Korea’s Punggye-ri Nuclear Test Site: Floodwaters Wash Out Bridges and Limit Access to the Test Tunnels
Commercial satellite imagery indicates that the portal area of North Korea’s Punggye-ri Nuclear Test Site incurred minor storm damage after the heavy summer rains, a pattern observed following the monsoon season year after year. Beyond flood-related activity, little else appears to have changed since our last update. Notably, no recent work has been detected either at Tunnel No. 3 (South Portal) or Tunnel No. 4 (West Portal).
Flood-related Damage
Year after year, monsoon season significantly affects North Korea, flooding various parts of the country and causing damage to homes, communities and farmlands. At Punggye-ri, in particular, heavy rainfall renders the site difficult to access, washing away vehicle bridges required to enter the site through mountainous terrain. This year was no exception.
On imagery from September 3, at least seven bridges have been washed away from the portal area to the command and control facilities. Several footbridges have been installed across the creek bed in the interim. Once rainy weather conditions abate and access to the site is restored, it could take several weeks before vehicle bridges can be fully replaced.
Tunnel No. 3 (South Portal)
Since restoring access to Tunnel No. 3 and rebuilding the surrounding and main support areas in 2022, there has been constant speculation that North Korea would conduct a nuclear weapons test. However, while the entrance to the tunnels appeared to be complete by August of that year, no new test has yet been conducted to date. Personnel are occasionally observed around this tunnel, but little other activity appears to have taken place since 2022.
Tunnel No. 4 (Former West Portal)
Imagery from January 2023 showed efforts had begun to regain access to Tunnel No. 4, the entrance to which had been demolished in May 2018. The access road to the original tunnel entrance was graded, and the surrounding hillside stabilized, enabling vehicle activity.
A wider area was cleared around the entrance near the creek bed, providing space for access to the tunnel network if and when needed. By April 24, 2023, a small shed was built in this area, potentially to protect the entrance of a future pilot tunnel to access the tunnel network. According to North Korean charts shown in 2018, only one test chamber was initially prepared for Tunnel No. 4 prior to demolishing the entrance, differing from the two test chambers available for Tunnel 3.
Imagery from September 3, 2024 follows similar patterns to previous rainy seasons, where landslides have led to ground instability around the portal. In order to access Tunnel No. 4, headworks will be required to stabilize the surrounding hillside, as was in place for the original portal entrance.
No further notable activity has been observed at the site. The reason for this extended hiatus in activity is unknown, though could be related to ground instability or a lack of need to reenter the tunnel, possibly due to no new developments to test.