WILLISTON, N.D.—From the looks of it, the nation’s boomtown is still booming. Big rigs, cement mixers and oil tankers still clog streets built for lighter loads. The air still smells like diesel fuel and looks like a dust bowl— all that traffic — and natural gas flares, wasted byproducts of the oil wells, still glare out at the night sky like bonfires.

Not to mention that Walmart, still the main game in town, can’t seem to get a handle on its very long lines and half­ empty shelves.

But life at the center of the country’s largest hydraulic fracturing, or fracking, boom has definitely changed. The jobs that brought thousands of recession­-weary employment­-seekers to this once peaceful corner of western North Dakota over the last five years have been drying up, even as the unemployed keep coming.

Downtown, clutches of men pass their time at the Salvation Army, watching movies or trolling Craigslist ads on desktop computers. The main branch of the public library is full, all day, every day, with unemployed men in cubbyholes. And when the Command Center, a private temporary jobs […]