colorado Plateau has them--high desert. I've experienced them often in both Arizona and New Mexico. I've seen a couple "wall" types of sandstorms (we tend to call them duststorms here). I don't think it really matters what part of New Mexico or Arizona that you live in. Sandstorms are pretty common occurrences for the area of New Mexico that I live in. I'm constantly fighting dust in the home as a result.

Phoenix was slammed with a bad one I think in 1999? Barbara probably remembers it. There's pictures of it somewhere.

They tend to be either like this:

[www.wrh.noaa.gov]

Or here's a picture I took in Arizona:

[img123.echo.cx]

The start can be dramatic if you're in the right place at the right time. Mostly, it just feels like they come out of nowhere and suddenly, your house is really dusty (even with the windows closed). Monsoon season is really pretty straight forward though. It starts with a sandstorm, then comes the rain and thunderstorm. Rinse and repeat anywhere between every day to every couple days over the course of a month or so and you have monsoon season. We get some pretty amazing electrical storms, too. We saw a bolt of lightening that was as wide as the two lane freeway we were on.

Stephanie

In every man there is something wherein I may learn of him, and in that I am his pupil.--Ralph Waldo Emerson