America's Two Major Desert Types: Great Basin and Sonoran

The US has four deserts, but two dominate by area and character: the Great Basin (cold) and the Sonoran (hot). They're fundamentally different worlds.

Great Basin Desert: Cold, High, Sagebrush

• Location: Nevada (most), western Utah, southeastern Oregon, slivers of Idaho/California
• Elevation: 1,200–2,000m (basin floors). Mountain ranges 3,000m+.
• Climate: Cold desert. Winter snow, subzero nights. Summer hot but dry. Rain: 150–300mm, winter-dominated.
• Vegetation: Sagebrush (Artemisia tridentata) ocean. Saltbush, greasewood, juniper-pinyon woodlands higher up.
• Hydrology: Internal drainage — no ocean outlet. Playas, salt flats (Bonneville, Black Rock).
• Iconic sites: Great Basin NP, Great Salt Lake, Black Rock Desert (Burning Man).

Sonoran Desert: Hot, Low, Biodiverse

• Location: Southern AZ, southeastern CA (Colorado Desert), northeastern Mexico (Sonora, Baja California)
• Elevation: Near sea level (Imperial Valley) to 1,200m.
• Climate: Hot desert. Bimodal rain: winter fronts + summer monsoon (July–Sep). 75–300mm. Frost rare/brief.
• Vegetation: Saguaro cactus (indicator), palo verde, ironwood, ocotillo, creosote, 2,000+ plant species — most biodiverse NA desert.
• Hydrology: Colorado River (heavily allocated), Gila River, ephemeral washes.
• Iconic sites: Saguaro NP, Organ Pipe Cactus NM, Joshua Tree NP (transition), Pinacate Biosphere (Mexico).

Why the Difference?

Latitude (Great Basin 38–42°N vs. Sonoran 31–34°N). Elevation. Rain shadow (Sierra Nevada blocks Pacific moisture from Great Basin; Sonoran gets Gulf of California moisture). Temperature regime defines everything.

The Other Two

Mojave (transition, Joshua trees, Death Valley). Chihuahuan (mostly Mexico, extends to TX/NM/AZ — creosote, tarbush, gypsum dunes).

Two deserts. Two thermostats. Two evolutionary laboratories.