The Bridger Bowl Cloud, affectionately known as the BBC, is a low hanging cloud cap that hovers over the east face of the Bridger Mountain Range and delivers an abundance of very dry snow to the Bridger Bowl ski area the locals call Cold Smoke.
This phenomenon is caused by Orographic Lift. Orographic lift occurs when an air mass is forced from a low elevation to a higher elevation as it moves over rising terrain. As the air mass gains altitude it quickly cools down adiabatically, which can raise the relative humidity to 100% and create clouds and, under the right conditions, precipitation.
Being on the east side of the continental divide Bridger Canyon gets the benefit of the prevailing winds hitting the Bridger Mountain Range, which forces the air to rise. Rising air is a requirement for precipitation. When air rises, it expands due to lower pressure. Expanding air cools, and cooler air allows the moisture in the air to condense into precipitation. This rising motion helps the air cool rapidly, and moisture condenses into snow.