SHOSHONI AND POWDER RIVER, SMALL TOWNS IN CENTRAL WYOMING, SHARE ONE LIFELINE: HIGHWAY 20. POWDER RIVER, POPULATION 44, HAS AN ELEMENTARY SCHOOL AND POST OFFICE. THE CARTOONISH COWBOY IS STILL CRAKING A SMILE. SIXTY MILES AWAY SHOSHONI, A FORMER OIL AND URANIUM BOOM TOWN, IS THE DRIEST TOWN IN THE MOUNTAIN TIME ZONE, SOMETIMES GETTING LESS THAN 4 INCHES OF RAIN ANNUALLY. PROSPERITY HAS DRIED UP AS WELL