Eastern Idaho's Snake River Plain and that portion of the Continental Divide bordering it to the north comprise a topographic feature that provides an interesting local wind phenomenon. A sloping discontinuity surface is produced in a zone of conflict between slope ** and valley winds. The incursions of the front at the National Reactor Testing Station have become the subject of investigation because of their effect on the dispersion of stack effluents*
Photographs are presented showing the effect of the frontal shear on a stack plume, smoke released at the ground, and a debris cloud from an experimental explosion. These photographs give an indication of the circulation pattern in the vicinity of the front. In addition, data from a network of recording stations, instruments on a 250-ft tower, and low-level wind and temperature soundings have been used to establish the circulation model.
Information is presented to show seasonal and diurnal effects, and also the influence of major pressure systems on the front phenomenon.
* Paper read at the 131st Meeting of the American Meteorological Society, September, 1954.
** The distinction here between slope wind, which applies to the steeper slopes of the sides of mountains, and mountain-valley wind, which applies to the gentler slopes of valley floors, is the same as that made by Wagner .