For the second straight year, the Bering Sea — a turbulent and bountiful stretch of the northern Pacific Ocean — is virtually ice free at a time of year when it should be gaining ice.

Expand chart Reproduced from Rick Thoman using NSIDC data; Chart: Axios Visuals

Why it matters: The ice pack's ebb and flow each year has far-reaching consequences for the broader Bering Sea ecosystem, including determining the reach and abundance of prized fish species such as Alaska pollock and Pacific cod. This is the richest fishing ground in the U.S., featured in the Discovery Channel's "Deadliest Catch."

The big picture: Scientists who keep close tabs on this region say the ice's early melt is upending life in the Last Frontier. It also portends consequences for the Lower 48 states and beyond. In a new study published in Earth's Future on Thursday, scientists warn that Arctic climate change is already reverberating far outside the region.

By the end of February, Bering Sea ice extent was lower than it has been since written records began in 1850.

The March 6 departure from the long-term average shows that an area of ice equivalent to California and Montana combined is missing from the Bering Sea.

Details: Rick Thoman, a scientist at the Alaska Center for Climate Assessment and Policy, tells Axios that a combination of unusually mild ocean waters and a persistent, anomalous weather pattern combined to decimate the region's sea ice cover: "One year maybe is a fluke, two years sure looks like we’ve crossed a threshold now.”

Since Jan. 23, a series of 16 powerful low-pressure systems have moved north from the Pacific into the Bering Sea region, bringing heavy precipitation and mild southerly winds.

These winds have vaulted warm, moist air into the region and northward into the Arctic. They've also broken up the thin ice cover.

The impact:

March is normally when people would be crabbing and fishing out on the ice. That's not happening now.

The sea ice loss makes hunting animals like walrus and seals, which serve as key food sources for native Alaskans in coastal villages, far more risky: It's much harder to haul a dead walrus into a boat than up onto solid ice.

Communities exposed to high seas are seeing severe erosion and threats to their infrastructure.

Diana Haecker, a reporter for the Nome Nugget newspaper in Nome, Alaska, tells Axios in an email: "The disappearance of sea ice and the ensuing weather is not only impacting our lives, it is disrupting life and is forcing each one of us, hunter or not, to refocus our energy on sheer survival."

Context: Zack Labe, a PhD candidate at the University of California at Irvine, says that although the past two years have brought historically low Bering Sea ice conditions, year-to-year trends there can fluctuate considerably.

Labe says some years may see temporary upticks in Bering Sea ice extent, but that overall, climate change is now in the driver's seat.

A study published last year found that a marine heat wave in the Bering Sea and Gulf of Alaska in 2016 cannot be explained without including human-caused global warming.

What's needed: Thoman says residents of the Lower 48 should be aware of and concerned about what's happening in Alaska: "The environment is changing and it’s impacting your fellow Americans now."

The bottom line: The loss of sea ice could change ocean temperatures, salinity and currents enough to alter the distribution and abundance of commercially valuable fish in this region. The stakes here are high, as the Alaska pollock fishery alone was worth $413 milion in 2017.