Compare the Loo, Chinook and Foehn winds with respect to their regions of prevalence, their nature and climatic impacts.

Nature

Hot, dry, dusty local wind.

• Summer afternoon wind
• Very high temperature
• Low humidity

Warm, dry downslope wind

• Adiabatically heated
• Rapid temperature rise
• Called “Snow Eater”.

Warm, dry downslope wind

• Adiabatic warming
• Develops on Alpine leeward side
• Gusty and dry

Regions of Prevalence

Northern & north-western India

• Indo-Gangetic Plains.
• Rajasthan, Punjab, Haryana, Delhi, U.P.

Eastern slopes of Rockies.

• Western Canada.
• Great Plains of USA

Leeward slopes of Alps

• Switzerland, Austria, southern Germany

Climatic Impacts

1. Intensifies pre-monsoon heatwaves across northern India, leading to extreme heat.
2. Causes a drying effect; thus, a sharp fall in humidity increases evapotranspiration.
3. Causes soil-moisture loss and crop/vegetation stress (Agricultural stress).
4. Carries dust, reducing local visibility and worsening thermal discomfort.
5. Human impact: Heatstroke and dehydration become common during intense spells.

1. Can cause a rapid rise in temperature within hours, thus leading to winter warming.
2. It accelerates snowmelt and reduces winter snow cover, known as snow eater.
3. Exposes pasture and provides temporary relief from severe winter cold.
4. Sudden snowmelt may increase local runoff.
5. Hazards: Rapid thawing can increase avalanche risk and damage vegetation.

1. Produces unusually warm and dry conditions north of the Alps (leeward warming).
2. Rapidly melts Alpine snow and shortens snow-cover duration.
3. Benefits agriculture as it can extend growing/ grazing conditions in Alpine valleys.
4. Hazards: Rapid snowmelt and strong gusts may increase avalanche and wildfire risk.