Following this thread, I notice several references to digging a trench for shelter, with the implication that it will be relatively easy - "scooping a half gallon of sand on every pass." Wish it were that easy.

The Sonoran Desert (and many others) has a surface that is primarily desert pavement - armor hard rock that is an absolute horror to dig through. Much of the rest is a charming substance known as caliche - I have spent two days using a full size pick and shovel to dig a hole for a rose bush right in my own back yard. There is very little dune sand anywhere in the Sonoran Desert.

For that matter, digging in soft sand is not that easy, either. I have dug, or attempted to dig trenches in beach sand without good results. The dry sand moves easily enough, but as you dig down, the walls simply slump and you wind up with a very shallow dished hole. When the sand is wet, you can get something like vertical sidewalls, but they are very likely to slump at any time. You could easily die seeking shelter in such a hole.

How did I learn about digging holes in desert soils? More than twenty years as an archeologist at places like Fort Bowie, Tonto, Tumacacori, Saguaro, Grand Canyon and other Arizona locales. The only easy way to punch in a hole in the desert is with a backhoe or dynamite.

Actually, the shelter solution is usually rather simple. Seek out natural stream banks, overhangs, and gullies. They are surprisingly common throughout much of the Sonoran area, although there is considerable variation from locality to locality.