Glen...while I don't think a lenticular cloud after Landers would be related, I was watching news reports of Northridge and there was an aftershock and there were very quickly large dust clouds to high levels. I could not figure out how so much dust could get so high so quickly...until much later I heard a talk about the landslides in the Santa Susana Mountains: some large percentage of these hills slid (shallow seated). I assume that landslides are the source of the dust. I don't think Landers caused extensive landslides (different geology, different topography). In the terminology of "Mythbusters", I think it plausible that a dust cloud would affect regular clouds: either makin them as condensation nuclei, or suppressing them because of change in density structure of atmosphere (I assume more dust= more dense so less likely to rise and make clouds. I am a weather buff of sorts and the National Hurricane Center tracks Saharan dust and I recall or mis-recall that they said that dust was suppressing convection.
Chris