Bengaluru early on Tuesday witnessed a record 180 mm rainfall in barely three hours, the heaviest downpour in August in over 120 years.
The rains wreaked havoc across the city, crippling normal life, flooding roads and houses in many localities and dampened the 71st Independence Day celebrations.
"As the downpour in just three hours (3 am to 6:00 am) was so heavy, the storm-water drains could not take the load in such a short time, resulting in rainwater overflowing on several roads and inundating low-laying areas," Bruhat Bengaluru Mahanagara Palika (BBMP) Commissioner Manjunatha Prasad told reporters later.
The torrential rains uprooted trees, twisted electric poles and snapped cable lines even in upscale residential areas across the city, disrupting power supply.
Civic officials had to use make-shift boats to rescue the stranded in some areas while power outages led to blackouts for hours since early morning in many areas.
"We received distress calls and complaints from hundreds of those affected regarding storm-water drains overflowing, and rainwater entering basements, ground floor houses and apartments," a civic official from the BBMP control room told IANS.
Police had a tough time during the day, as several arterial roads, subways and underbridges were waterlogged, slowing vehicular movement and causing traffic snarls.
According to the Meteorological Department, the city had not witnessed such a heavy rainfall in August since 1890 when 166 mm rain was recorded on a single day.
Scientist C N Prabhu of the Karnataka State Natural Disaster Monitoring Centre admitted that the weather monitoring system did not predict the heaviest rainfall in the city after 127 years.
"We had forecast a moderate rainfall but it developed into much heavier than we could predict. It is certainly 3-4 times heavier than the prediction," Prabhu told IANS.
"There was a thick patch of clouds over the city that caused the downpour. Being the monsoon season, heavy rains are not unusual," Prabhu added.