First the gold rush. Then the slowdown.

"The luckiest place on earth" is how Chip Brown characterized today's North Dakota, flush in its energy frenzy. His article in the New York Times Magazine showed chief execs and miners both giddy about their topographical luck and only slightly nervous that this boom would end as the last ones have -- in a bust.

To borrow a line you'll hear tonight, let me be clear: North Dakota is not busting. It led the 2012 national job creation index -- with both the highest hiring rate and the lowest firing rate of any state in the country, for the fourth straight year. Here are the top five states for hiring, according to that Gallup poll, with their indexed 2012 growth from BLS figures.

This chart tells two stories about America's little petro state. First story: At the beginning of 2012 (much like in 2011 and 2010), North Dakota's stratospheric job creation numbers made even the next frothiest states look like they're were suffering a post-Soviet-breakup depression. Second story: Something happened in the second half of 2012. North Dakota's economy fell back to earth.

Let's dig deeper. Here's the graph of 2011 job creation across North Dakota industries versus the last six months of 2012.

You might say, don't be unfair, North Dakota never could have kept up its 2011 rate!, and I might respond, you're right. If the U.S. had experienced Dakotan growth across 2011, we would have added about 400,000 jobs per month, and that's just absurd.

Still. The drop-off is striking, and it's not without explanation.

Let's begin at the left, with mining. The rig count across North Dakota, and particularly in the rich Bakken shale, dropped sharply in September and hiring has slowed since the summer, as drilling companies have turned their focus to efficiency as capital costs (and concerns of regulation) rise in the Bakken. That's probably had spill-over effects in transportation hiring. The story in construction is a story about migration. The state's population grew by four percent according to Census figures between mid-2010 and mid-2012. That would be like the entire U.S. adding an extra Pennsylvania in two years. As a result, new houses blossomed in the late 2011 and 2012, but that ridiculous bump (see below) has returned to trend-line growth, which has slowed down construction hires.

The only large private sector category that is growing faster now than in 2011 is hotel and food services jobs, at the far right of the second graph. These jobs are lagging indicators of population growth because they respond to growing cities.

This is how an energy boom should go, you could argue. First come the core mining jobs and manufacturing jobs. Then you build the houses and roads to accommodate the miners and factory workers. Then you open restaurants to feed their families. And you build hotels to room their visitors and petro-tourists. That's not a bust story. It's a modern growth story.

Okay, fine. Perhaps that's all the North Dakota slowdown is. Chapter Two in North Dakota's modern gold rush. The state's job creation isn't weak, after all, it's just, well, average. But that's just the problem. When you're girded for a historic gold rush, average growth isn't average news. It's bad news.