Frankly it sounds like the writer is talking about Los Alamos or the
Jemez. For sake of argument let us assume we are talking about north
central NM. The air is very dry most of the year (<20% humidity some
days approaching 0%). When the jet stream comes down it brings a lot of
upper air moisture (ice particles). That brings two of the requirements
for a funny rainbow effect. In the late 1960's the Navajo built a power
plant near four corners that was a horrible polluter. The Rio Grande
valley would literally fill up with pollution, mostly white. The sun
certainly could be reflected off that surface, giving the third and last
requirement, even when there are no clouds. That said, I lived in New
Mexico for 21 years and never saw anything even approaching that. One
day, though, I was driving from the Jemez Pueblo to Cuba NM and there
was a rainstorm over Mt. Taylor. With this storm there was a HUGE
double rainbow. If I had been in a canyon looking at the part of the
rainbow near its peak I think it would look like a series of straight
lines.