The hot, dry wind on the east or leeward side of the Rocky mountains (North America) is called

the Chinook
the Sirocco
the Harmattan
the Loo

The correct answer is A. the Chinook.

A Chinook is a warm, dry wind that blows down the eastern slopes of the Rocky Mountains in North America. It is caused by the rapid descent of air that has been heated by compression as it flows over the mountains. Chinook winds can raise temperatures by as much as 50 degrees Fahrenheit in a matter of minutes. They are often accompanied by clear skies and a strong, gusty wind.

The Sirocco is a hot, dry wind that blows from the Sahara Desert across North Africa and into southern Europe. It is caused by the difference in pressure between the hot, dry air of the Sahara and the cooler, moist air of the Mediterranean Sea. The Sirocco can cause high temperatures, low humidity, and dust storms.

The Harmattan is a hot, dry wind that blows from the Sahara Desert across West Africa. It is caused by the difference in pressure between the hot, dry air of the Sahara and the cooler, moist air of the Atlantic Ocean. The Harmattan can cause high temperatures, low humidity, and dust storms.

The Loo is a hot, dry wind that blows from the Thar Desert across northwestern India. It is caused by the difference in pressure between the hot, dry air of the Thar Desert and the cooler, moist air of the Indian Ocean. The Loo can cause high temperatures, low humidity, and dust storms.