Greenland’s glaciers are melting extremely fast this year, and the runoff is flooding rivers with waves so great they wiped out a bridge crossing the Watson River near Kangerlussuaq.

The Russell Glacier feeds the Watson River, which is best suited for a usual season of partial ice melt. The glacier rests entirely on land, so its runoff must travel through rivers and streams to reach the ocean, tearing at the riverbeds and surrounding infrastructure not suited for such massive flow. Some of the water may freeze along the way, and scientists are trying to determine just how much this glacial melt will affect sea levels.

Satellites revealed that nearly the entire ice cover of Greenland had melted by July 12, going from 40 percent melt to 97 percent melt in just four days. Only about half of the sheet melts during an average summer. NASA scientists believe the rapid melting is the result of a cover of warm air, called a heat dome. The extremely rapid rate has stunned scientists, many hoping the data was flawed, and further convinced many about the realities and destruction of climate change. Still, there is a possibility this could be considered a normal event, and some researchers want to see more data before worrying too much.

“Ice cores from Summit show that melting events of this type occur about once every 150 years on average. With the last one happening in 1889, this event is right on time,” said Lora Koenig, a Goddard glaciologist and a member of the research team analyzing the satellite data. “But if we continue to observe melting events like this in upcoming years, it will be worrisome.”

Temperatures in Greenland have been rising five times faster than the global average, rising four degrees in the past 30 years. Even if this melting is a once-every-150-years event, chances are we are seeing what will become the norm not too far down the line.

Main image credit: NASA; video credit: Kangerlussuaq Science Field School