Mini Cloudbursts

Source: TH

Context: The IMD clarified that while there is no rising trend in major cloudbursts, instances of “mini cloudbursts” are increasing in India.

About Mini Cloudbursts:

• What it is? A mini cloudburst is a sudden, high-intensity rainfall event defined as ≥5 cm of rain in an hour over a small area (~20–30 sq km), less severe than the IMD’s official cloudburst criterion (≥10 cm/hr).

• A mini cloudburst is a sudden, high-intensity rainfall event defined as ≥5 cm of rain in an hour over a small area (~20–30 sq km), less severe than the IMD’s official cloudburst criterion (≥10 cm/hr).

• Criteria:

• Rainfall intensity: ≥5 cm/hour. Localised area: ~20–30 sq km. Duration: Short-lived but extremely intense.

• Rainfall intensity: ≥5 cm/hour.

• Localised area: ~20–30 sq km.

• Duration: Short-lived but extremely intense.

• Features:

• More frequent than full cloudbursts. Short-range prediction remains impossible; only nowcasting of heavy clouding/rain is feasible. Often unrecorded due to lack of ground stations in remote areas; satellite imagery has limited precision.

• More frequent than full cloudbursts.

• Short-range prediction remains impossible; only nowcasting of heavy clouding/rain is feasible.

• Often unrecorded due to lack of ground stations in remote areas; satellite imagery has limited precision.

• Regions Affected:

• Himalayan states: Himachal Pradesh, Uttarakhand, Jammu & Kashmir, Ladakh. Urban hotspots: Chennai (example, Aug 30, 2025), Mumbai, Delhi NCR. Regions with orographic influence (mountains forcing air uplift).

• Himalayan states: Himachal Pradesh, Uttarakhand, Jammu & Kashmir, Ladakh.

• Urban hotspots: Chennai (example, Aug 30, 2025), Mumbai, Delhi NCR.

• Regions with orographic influence (mountains forcing air uplift).

• Implications:

• Trigger flash floods, landslides, and infrastructure collapse even at 2–5 cm/hour rainfall in hilly terrain. Severe loss of lives, crops, and property. Strain on disaster preparedness and climate resilience policies.

• Trigger flash floods, landslides, and infrastructure collapse even at 2–5 cm/hour rainfall in hilly terrain.

• Severe loss of lives, crops, and property.

• Strain on disaster preparedness and climate resilience policies.