Posted by Rick H (208.23.111.4) on November 30, 1999 at 21:38:27:
In Reply to: Interesting Case? posted by dwd on November 30, 1999 at 16:52:56:
I started having clusters one year apart when I lived at about 1400 ft asl (above sea level) and continued for several years at once or twice a year. I moved to 7600 ft asl and after about six years to 5000 ft asl and didn't have a cycle for more than ten years. Then I began having annual cycles again (still at 5000 ft asl). I moved to 800 ft asl and didn't have a cycle for two years and then moved to 2000 ft asl and am having annual cycles again. My conclusion? Altitude is not a factor for me.