1. Fallen Power Lines

• Heavy rain is often accompanied by strong winds or lightning, which can knock down trees or branches onto power lines.

• When power lines fall, they can cause widespread outages until they’re repaired.

2. Short Circuits and Electrical Faults

• Rainwater can seep into transformers, junction boxes, or cables if they’re not properly sealed.

• Water conducts electricity, so it can cause short circuits or tripping of protective systems, shutting down power as a safety measure.

3. Lightning Strikes

• Lightning can strike power lines directly or indirectly, damaging electrical equipment like transformers or causing circuit breakers to trip.

• Utilities often shut parts of the grid down briefly to prevent damage or fire hazards.

4. Poor Infrastructure or Maintenance

• In some areas, aging power infrastructure (like rusted transformers or exposed wires) is more vulnerable to weather.

• Lack of maintenance makes it easier for rain to trigger faults or weaken equipment.

5. Flooding

• Floods can damage underground power lines, substations, and switchgear, leading to prolonged outages.

• Electrical utilities often cut power proactively in flood zones to prevent electrocution.

Summary:

Rain causes blackouts mainly due to equipment failure, falling trees, short circuits, or preventive shutdowns. The more vulnerable the infrastructure, the more likely a blackout becomes during storms.