Harold Hamm, the CEO of the biggest oil producer in North Dakota's Bakken range, finished the scripted portion of his explanation of first quarter results Thursday by saying, "I assure you we're almost done talking about North Dakota weather."

For Hamm's Oklahoma City-based Continental Resources Inc., the brutal winter in western North Dakota and much of the Upper Midwest did surprisingly little to slow its rapid growth. Broader measures of production in North Dakota showed lower output during the winter months following a peak in November. But Continental Resources said it produced the equivalent of 97,000 barrels a day during the first three months of the year, up 4% from the last three months of 2012 and 27% from the same period a year ago.

The company accounts for about 10% of all production in the Bakken. And Bakken production accounts for about two-thirds of its output; it also has a major play in southern Oklahoma.

But the severe winter did slowed down its ability to complete new wells. Executives said most of the 70 wells it completed during the quarter happened in March. A backlog of wells that have been started but aren't yet completed, or producing oil, grew and the company has hired extra crews to work it down.

Even as temperatures warmed up, some work was slowed by spring thaw restrictions that are designed to prevent trucks and big machinery from chewing up roads and land, Continental Resources executives said.

The company's profit rose 70 percent but its per-share figure missed analysts' target by 3 cents and its stock fell Thursday. Executives blamed the profit miss on a buildup in inventory that had to be stored near well sites in North Dakota because trucks and rail cars experienced weather-related delays.

Hamm said, "We anticipate much better operating conditions in the next several weeks. We're ready to shift into high gear."