BCS North - Phase 1: 0.33× baseline latency
What we measured
| Cable | BCS North - Phase 1 |
| Segment | Stavsnas, SE → Helsinki, FI |
| Detected | 2026-04-17 19:02 UTC |
| Resolved | 2026-04-17 20:31 UTC |
| Duration | 1h 29m |
| Observed latency | 12.6 ms |
| Baseline | 38.6 ms · 0.33× |
| Increase | +137% |
| Severity | warning |
Who is affected
Countries where BCS North - Phase 1 comes ashore, how much of their submarine diversity this cable represents, and what our measurements into them show.
| Country | Dependence on this cable | Other submarine cables | What the measurements show |
|---|---|---|---|
| Finland resilience index: 100 · resilient |
1 of 15 cables (7% of submarine diversity) | Baltic Sea Submarine Cable, BCS North - Phase 2, Botnia +11 more | no measurement today; median 55 ms over 30 days (10 routes) |
| Sweden resilience index: 100 · resilient |
1 of 29 cables (3% of submarine diversity) | Baltic Sea Submarine Cable, Baltica, BCS East-West Interlink +25 more | median 68 ms today vs 71 ms over 30 days (42 routes) - unchanged |
Dependence is structural (share of the country's submarine cables), not a traffic share: real traffic distribution across cables is not public.
Path analysis
Traffic kept the same route. Latency rose without a visible path change, which points at congestion or a fault on the existing route rather than a reroute.
Cross-probe verdict. Some probes saw the degradation and others did not, which usually means a partial or regional effect.
Timeline
- Alert 2026041707: warning - ratio 2.37x
- Alert #85 improving: 1/3 consecutive OK
- Alert #85 resolved: RTT 12.62ms (baseline 38.61ms), 3 consecutive OK
Detection method
Latency is sampled continuously from our probe network. An alert opens when round-trip time to a monitored endpoint holds above its rolling baseline, and closes automatically once it returns. Full method is described on the methodology page.