What is the name of the cold desert that covers most of the Patagonian steppe?

The cold desert covering most of the Patagonian steppe is the Patagonian Desert.

Also called the Patagonian Steppe, it stretches mainly across southern Argentina, with related areas extending into Chile. It is a cold winter desert rather than a hot tropical desert: temperatures are generally low, frost is common, and precipitation is limited. Shrubs, hardy grasses, and other drought-tolerant plants dominate the landscape.

The Andes help create this aridity. Moist air arriving from the Pacific loses much of its water as it rises over the mountains, leaving the eastern side in a rain shadow. Strong, persistent winds further dry and erode the exposed plateaus and gravel plains.

The Patagonian Desert is often confused with Chile’s Atacama Desert, but the two have different settings. The Atacama is an exceptionally dry subtropical desert in northern Chile; the Patagonian Desert is a cool, windy desert of the far south. Its terrain includes river valleys, canyons, volcanic formations, and glacial lakes.