Cross-checking many nearby sensors before firing an alert cuts false alarms while still catching a real extreme event early.
alert fires when local_signal > threshold
lead_time ~ mesh_density
- Sensor nodes — rain gauges, river-level and wind sensors forming the early-warning mesh.
- Sensor mesh density — how tightly the sensors are interconnected for cross-checking.
- Signal input rate — how frequently raw hazard readings arrive from the field.
- Alert threshold — signal strength required before the mesh escalates to a public warning.
Early-warning systems cut cyclone and flood mortality by an order of magnitude when lead time exceeds a few hours — the UN's Early Warnings for All targets full global coverage by 2027.