When most people think of the Arctic, they usually imagine things like polar bears and Santa Clause. What they don’t picture are waves the size of a one-story house, because most of the Arctic Ocean is typically frozen and you can’t have big waves in frozen water. Well, tell that to the scientists from the University of Washington and the Naval Research Laboratory, who recently published their 2012 observation of big waves in the Arctic’s Beaufort Sea: During peak times, the waves averaged around 16 feet high.

The highest single wave was measured at 29 feet. Researchers fear that the waves, enabled after decades of expanding ice retreat thanks to global warming, will even further accelerate the ice breaking process in the Arctic region.

“The observations reported here are the only known wave measurements in the central Beaufort Sea,” they wrote in the report, “because until recently the region remained ice covered throughout the summer and there were no waves to measure.”

To create waves, you need plenty of open water in addition to high winds. There were no waves observed earlier, because in the past the ice just didn’t retreat far enough, even in the heat of summer.

Now, things are different. “In recent years, the seasonal ice retreat has expanded dramatically, leaving much of the Beaufort Sea ice free at the end of the summer,” they wrote.

Though no one is sure of anything just yet, the shocking observations don’t paint a rosy future. The compounding effects of sea swells combined with global warming could have unseen consequences for all who inhabit the Arctic, both human and otherwise. What exactly those consequences will be is the subject of future study.

“Waves could accelerate the ice retreat,” researcher Jim Thomson told the Washington Post in an email.  “We don’t have much direct evidence of this, or knowledge of the relative importance compared with melting, but the process is real.  We are conducting a large project this summer to answer just that question”