– Angry moose. Waist-deep snow. Fatigue. River ice overflows.

The Iditarod Trail Invitational (ITI), a winter bike and foot race that starts March 1 on Alaska’s famed sled dog trail, is as unpredictable as it is challenging.

“As far as fatbike racing goes, it’s kind of the pinnacle,” said Ben Doom, 39.

To prepare, the first-time ITI competitor from St. Cloud fits four-, six- and eight-hour rides between the commitments of work (he co-owns Revolution Cycle & Ski) and family (his three daughters are younger than 12).

“You ride as much as time allows,” Doom said on a recent morning before work. “It’s been tricky this year because of the lack of snow. So I’ve been traveling to try and find snow.”

To qualify for the 350-mile, off-the-grid route through the Alaskan brush, competitors must have three to five finishes in winter endurance races on their resume.

Doom’s includes three Arrowhead 135 finishes. That human-powered race on a snowmobile trail from International Falls to Tower, Minn., shakes out more than half its competitors before the finish line. He’s also completed Wisconsin’s 150-mile Tuscobia Winter Ultra and Idaho’s JayP’s Backyard Fat Pursuit.

“I’m super excited to do it,” Doom said of the ITI, “but until you do a race like this a few times, there’s so many unknowns that I’m never going to be fully prepared for it. So I want to get started.”

This year, poor snow conditions moved the Iditarod sled dog race start 300 miles north to Fairbanks. The ITI will begin, as planned, from a point north of Anchorage. It will still cross the Alaska Range — but without the benefit of a trail groomed by snowmobilers preparing for the sled dog race.

The cold could be Doom’s biggest hurdle.

He’s sought advice from other racers. From a Fairbanks source, he received a list of what to do at 20 below, 30 below.

“He ends at 50 below. Fifty below?” Doom said.

Keep moving. Don’t stay in one spot too long.

Doom will heed that advice, plus he will keep a sleeping bag, puffy jacket and change of socks handy. He’s consulted with fellow Minnesotan and fatbike racer Mark Seaburg, 55, a Minneapolis-based physician.

“We both know how to ride our fatbikes in the cold. The problem is going to be to ride them almost three times longer than we have anywhere else,” Seaburg said by phone.

Doom expects to finish the race in three to five days but has allowed for up to seven on the trail.

Last year’s 350-mile winner finished in two days, four hours, 43 minutes. Two Minnesotans finished in the top five. In 2012, the winner finished in six days, 15 hours.