(David Fifield)
A major event happened in June 2025: a near-total Internet shutdown in Iran that lasted about 2.5 days. It has long been the case that users from Iran form the largest group of users of the snowflake-01 bridge, when broken down by country. The shutdown therefore had a large effect on Snowflake usage.

First, have a look at the concurrent users and bandwidth graphs. We see a ramp up starting on 2025-06-12, followed by a sharp decline on 2025-06-18, then another ramp up starting 2025-06-20.

The graph of users by country sheds more light on the story. The shutdown in Iran began on 2025-06-18 and ended on 2025-06-21. But about a week before that—starting 2025-06-12—the number of users in Iran suddenly nearly doubled. The cause for this preliminary increase is not known. See issue #40465 for discussion among the Tor anti-censorship team about the change in traffic volume. The discussion also shows the effects of the ensuing shutdown.

We see the line representing Iran drop off the graph on 2025-06-19 after the shutdown began. There were very limited options for connectivity in Iran at this time. Investigation revealed that an IP address of google.com was still accessible, which made it possible to access the Google AMP cache. It seems that users were able to rendezvous with the broker using Snowflake's AMP cache rendezvous, but the subsequent WebRTC connection to the proxy was blocked anyway.

The total shutdown ended on 2025-06-21, but immediately after that there was an interval of abnormal network access that lasted until 2025-06-25. We see the number of users climb back up rapidly at that time, to levels higher than before the shutdown.

There continued a decline in users from Turkmenistan following the massive increase in April 2025. But even the estimated about 1,000 concurrent users at the end of the month is historically high for Turkmenistan.