It's not a common thing. And they don't "explode" as much as shatter. It does require enough sap to be up in the tree trunks too. And our trees are too smart to let that happen for the most part. But it can and does happen sometimes to thin spindly young trees.

It's been pretty cold up here in far northern Minnesota since last Wednesday. With morning temps at -25F, -30F, -30F and -35F this morning. The high yesterday was -15F and a high of -5F today. It's not the very low temps that bother anyone up here, it's the windchill that will kill you. Yesterday, the wind chills were running -35F to -60F. Which can cause frostbite to exposed skin in 5 minutes or less and possibly kill you very quickly.

On the upside, at these temps large amounts of snowfall are almost impossible. So I won't need to start a tractor and plow the mile and a half to the nearest plowed road.

It's not just about the temperature, it's also about how quickly the temperature is dropping. Usually when the temperature goes down, trees do some "clever" shit with the sap inside them, specifically so that there's less moisture in them and when it freezes and expands the tree doesn't crack. However if it drops too quickly the trees can't do their magic quickly enough, too much water freezes, puts too much stress on the tree and it may crack.