The Arctic circle is having a really, really weird spring, and not at all in a good way. We knew global warming was speeding up, but it’s now getting hotter so quickly that climate scientists studying the ice sheet in Greenland briefly thought their measurements were completely wrong.

Earlier this year we officially passed the point of no return when it comes to climate change, which is a largely arbitrary gauge of exactly how screwed we are. Temperatures in February were 1.4 degrees Celsius above what they normally are that time of year. March was warm too, and on Monday, it became clear that April was absolutely not going to make anything better. Slate’s resident meteorology columnist Eric Holthaus turned up some data from the Danish Meteorological Institute that showed that 12% of the entire ice shelf over Greenland experienced some melting on Monday. PolarPortal, a Danish government website covering all things icy, published the data and some quotes from the scientists studying the ice shelf. Apparently, when the scientists saw the crazy spike in the percentage of the shelf that was melting, it was so out of the ordinary they thought they’d messed up their measurements. See for yourself — the below graph shows the average percentage of total ice sheet that’s warm enough to melt — the dark grey curve is average (from 1990-2013), and the shaded area is the year to year variation.

The grey line is normal. The blue line is this year. It should not look like that.

“We had to check that our models were still working properly,” Peter Langen, a climate scientist at DMI told PolarPortal. Fortunately (or unfortunately, if you live in a coastal city), the researchers saw that temperatures were well above freezing on the top of the ice shelf, as high as 50 degrees Fahrenheit in some places, which “helped to explain the results.”

Unseasonably warm temperatures also help explain some of the weirder things we’ve been seeing this spring, like the time when a group of snowmobilers had to tow canoes behind their ‘mobiles after a bunch of snowmelt overflow covered an iced-over lake with six inches of water.

It’s not completely surprising though, as temperatures are just absolutely batshit insane right now — as much as 68 degrees Fahrenheit higher than averages in Greenland.

The DMI says this change is driven by a bunch of warm air coming in and forming a “cap” over the island, while cold air and low pressures hover around to the east and west. The last time this specific situation happened was in 2012, when the freakish circumstances caused 95% of the ice shelf to melt (it’s worth noting that we don’t mean literally all the ice melts, just that temperatures over 95% of the surface area are at the melting point. There’s a lot of ice in Greenland.)

Things should cool down again this week, but more of the same air pressure and temperature currents could mean we get a lot more melting this weekend. Either way, as welcome as spring weather is in most of the world, warm rain is not a good thing in a place that’s usually supposed to be covered in ice.