What happened

Attackers obtained remote access to an operational-technology control panel at a dam by Lake Risevatnet, changed its settings and left a discharge valve fully open for about four hours. Norwegian authorities reported a flow of roughly 500 litres per second before the manipulation was detected and stopped. NSM said the event had apparently limited physical and economic consequences, while PST attributed it to a pro-Russian hacktivist group. The dam supplies water to a fish-farming facility; public reporting often called it a hydropower dam, but the reviewed official material does not establish that the affected system generated electricity. The marker is approximate.

When cited sources give different casualty, damage or spill figures for this event, they’re reported side by side above rather than merged into one number. See how confidence levels work.