STORM TRACK: May 31, 1979 (Volume 2 Issue 4)

Rainbows have often been considered to be the quiescent mark of a storm's end, but some can indicate the severity of a mature thunderstorm. During the Summer of 1978 while storm chasing in Oklahoma and Kansas, three separate occurrences of unusual rainbows were observed.

These unusual rainbows were double rainbows. A double rainbow consists of two other rainbows, a primary and a secondary. A primary rainbow is the outside rainbow, having colors from red to violet with red on the outer border. A secondary rainbow is the inner rainbow with color bands reversed from the primary, violet on the outside border.

The double rainbows were only seen when the chasers were to the west of a thunderstorm and the sun was to the west of the chasers at an elevation between 5 and 40 deg above the horizon. Relatively clear air existed between the sun and the storm. Also of note, a whitish precipitation shaft was observed from the storm.

Upon entering the shaft, abundant rain and small hail was encountered, with hailstone diameters from 1/8 to 1". The Index of Refraction for water is 1.333 and for ice is 1.305 which indicates that ice is a better mechanism for producing rainbows. Or are they called hailbows or hainbows?

All storm chasers are encouraged to keep an eye out for unusual atmospheric phenomena, and to investigate the phenomena as completely as possible If anyone has experienced such hainbows, please contact the following: James S. Lynch, The Severe Storm Intercept Project, P.O. Box 3305, College Station, Texas 77840.