A storm does not need a name to become dangerous.

Odisha saw that when a powerful weather system flooded roads, shut schools and disrupted life across coastal and inland districts. Baleshwar recorded 246.6 mm of rain in 24 hours, while Balasore town received around 204 mm during the reported period, according to Hindustan Times.

The deep depression in bay of bengal never reached cyclonic-storm strength. Yet it carried enough moisture to overwhelm drains, submerge neighbourhoods and raise the risk of flash floods.

That is why the system mattered: wind speed was not the biggest threat. Rainfall was.
 

Deep Depression in Bay of Bengal: What Happened?

A deep depression is an organised low-pressure system. It is stronger than a depression but weaker than a cyclonic storm.

The India Meteorological Department classifies it as a system with maximum sustained winds of about 50–61 kmph. A cyclonic storm begins when sustained winds reach 62 kmph, according to the IMD’s cyclone warning procedure.
 

This classification measures wind strength, not rainfall. A deep depression can therefore trigger severe flooding without becoming a cyclone.
 

How Did the Weather System Form?

The system began as a low-pressure area over the northwest Bay of Bengal.

On July 26, the IMD said it had strengthened into a well-marked low-pressure area and then concentrated into a depression. At 8.30 am, it was around 180 km east-southeast of Balasore and 170 km east of Chandbali, according to the agency’s July 26 press release.
 

Warm, moisture-rich air fed the system, while the active monsoon trough supported widespread rain.

As its circulation became organised, it strengthened into a deep depression in bay of bengal near the West Bengal–north Odisha coast.

By 8.30 am on July 27, it was around 120 km east-southeast of Balasore. The IMD warned of very heavy to extremely heavy rain at isolated places in Odisha in National Bulletin No. 6.
 

When Did It Cross the Coast?

Early forecasts suggested a July 27 crossing, but the system moved more slowly.

The IMD later confirmed that it crossed the West Bengal–north Odisha coasts close to Digha between 12.30 am and 1.30 am on July 28. By 5.30 am, its centre was around 30 km northeast of Balasore, according to National Bulletin No. 10.

It then moved west-northwestwards across northern Odisha, carrying heavy rain inland.
 

Why Did It Cause Extreme Rain Without Becoming a Cyclone?
 

Four factors made the system dangerous.

It carried large amounts of moisture

The Bay of Bengal supplied warm, moisture-rich air. As that air rose and cooled, it formed thick rain clouds.

It moved slowly

During one observation period on July 27, the system was moving at around 3 kmph, the IMD bulletin said.

A slow system can send repeated rain bands over the same area, pushing totals higher.

The ground became saturated

Repeated rain left the soil unable to absorb more water. New rainfall then flowed into streets, drains and low-lying settlements.

Urban drains became overwhelmed

When rain falls faster than drains can remove it, roads and homes flood quickly.

 

Why Was Baleshwar Hit So Hard?

Baleshwar, also called Balasore, lay close to the system’s path.

The district recorded 246.6 mm of rain in the 24 hours ending Tuesday morning. Balasore town received around 204 mm, according to Hindustan Times.

Low-lying neighbourhoods were submerged. Traffic slowed, drainage teams were deployed and fire-service personnel prepared for possible evacuations.

The report also cited district figures of 405 mm on July 26 and 354 mm on July 27. These may reflect different gauges or reporting periods, so they should not be added as one total.
 

Which Odisha Districts Were Affected?

Authorities closed government, government-aided and private schools in Balasore, Bhadrak, Mayurbhanj, Sambalpur and Kendujhar. Anganwadi centres also remained closed, Hindustan Times reported.

The IMD also warned of possible flash flooding across several coastal and inland districts in National Bulletin No. 6.

 

How Did It Affect West Bengal?

The system also changed the West Bengal weather outlook.

Very heavy rain was forecast for Paschim Medinipur and Jhargram. South 24 Parganas and Purba Medinipur faced heavy downpours. These West Bengal weather warnings showed that the rain bands covered a wide area.

During the 24 hours ending at 8.30 am on July 27, Sagar Island recorded 52 mm of rain. Kanthi received 34 mm, Haldia 29 mm and Canning 21 mm, according to a PTI report published by The Economic Times.

 

What Did It Mean for Rain and Kolkata?

The Bengal rains were strongest in coastal and adjoining districts, but Kolkata also remained cloudy and wet.

The IMD forecast a generally cloudy sky with one or two spells of moderate Kolkata rains through July 28. Kolkata did not receive the same totals as the hardest-hit coastal areas, but wet roads and lower visibility could still affect travel.

Isolated heavy rain was also forecast for Darjeeling, Kalimpong, Jalpaiguri, Alipurduar and Cooch Behar, according to the same PTI report.

The wider Bengal rains showed how one system could affect coastal, urban and northern districts together. Further Kolkata rains could still slow traffic.

Internal link: Add TUI’s Kolkata monsoon or waterlogging explainer here.

 

Why Were Fishermen Told to Stay Ashore?

The IMD forecast squally winds of 50–60 kmph, gusting to 70 kmph, and rough to very rough seas in National Bulletin No. 6.

Fishermen were advised to avoid the northwest Bay of Bengal and adjoining coastal waters until the morning of July 29.

Rough seas can destabilise small boats, while rain and sudden gusts make navigation dangerous.
 

Can Flooding Continue After Coastal Crossing?

Yes.

A deep depression usually weakens over land, but its rain does not stop immediately. Clouds can move inland, while rivers may rise later as runoff reaches them.
 

What Should Residents Do?

Residents should avoid flooded roads, drains and damaged power lines. Families in low-lying areas should follow IMD and district alerts, and keep medicines, documents, drinking water and charged phones ready.
 

The Bigger Lesson

The deep depression in bay of bengal did not need cyclone-force winds to create a serious emergency.

Its slow movement, moisture supply and repeated rain bands flooded neighbourhoods, closed schools and disrupted transport across Odisha.

The lesson is clear: rainfall intensity, movement speed, drainage capacity and local geography can make a deep depression dangerous long before it becomes a named cyclone.