People look at me funny when I tell them I used to have exploding head syndrome.

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.

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.

20° is close to the temperature where it doesn't matter

The use of the word "explode" is misleading. It's definitely misinformation.

Here's an arborist talking about it, but basically:

Trees move sap and other liquids up and down their trunk from the soil underneath regularly. For trees like maples, this is where maple syrup comes from, except you have to collect a lot of sap and reduce it down to syrup.

The arborist claims that these liquids present in the tree when the temperature swings faster than the tree can respond expand due to freezing, which buckles tree trunks causing the outer bark to crack open and separate. The cracks can be from the ground up, or they can look like gashes in the side of the tree. There's moisture in the soil too, which can shift tree roots and cause similar cracking.

People say "explode" because there's usually a popping sound when this happens.

In other contexts, people call this frost upheave. Engineers know about this phenomenon, and try to bury equipment like pipes and cable and conduit below the frost line so frost upheave doesn't crack and break that stuff. With trees, this frost upheave just takes place inside the trees themselves.

The trees don't "explode" but young spindly trees can shatter if the conditions are just right, (and they are not right now). It's very rare to have happen.

Source: I live in northern Minnesota. And I live closer to Winnipeg than the Twin cities.

I'm going to guess it has to do with how quickly the temperature change occurs, or other environmental factors prior to the freeze. It seems to be a somewhat rare occurrence, even in places where it gets very cold

It isn't common, and explode is an exaggeration for what I have seen - just cracked bark (though the crack was probably abrupt and loud). Montana gets some every now and again, so I am guessing at least some parts of Alberta do too. Nobody has made a big deal about it in the past outside of folks interested in trees. This is some weird media hype.

Trees further south have different conditions.

When we get cold snaps before 15f in the mid Atlantic tree sap that doesn’t usually freeze will freeze and limbs will pop. I’ve never seen a tree explode but I’ve definitely heard trees blowing limb and bits of themselves in the woods. Wind exacerbates the phenomenon

The United States is very big. If you're from a smaller country (particularly if it's smaller east-to-west), it can be a little bit hard to comprehend how different the weather can be from one part of the country to another. While the weather does typically travel from West to East, it can change significantly along the way, and it usually takes several days to get from one coast to the other.

The highlighted area on the map is a massive region, wider than France and Germany put together (though much less populated). In fact, it's quite rare for even this much of the country to have the same weather pattern. The simplest answer to why trees to the east and west are safe is that it's not as cold there.

There are some other factors, too: just past the Western edge of the highlighted region are the Rocky Mountains, which significantly change weather patterns. The highlighted region consists of remarkably flat land (leveled by glacial action), meaning that there's not much to break the wind as it sucks away the heat from the trees. To the East if this highlighted region are the Great Lakes, which also change weather patterns.

But the biggest answer is, it's just not as cold there. Cleveland, OH (at a similar latitude, but further to the East) is going to be almost 20°F warmer than this (which is still bone-chilling, but not tree-exploding), and Boise, ID (similar latitude but to the West) is going to be almost 40°F warmer (practically tropical! /s).

It's also worth noting, if you're not familiar with the US map, that the city of Minneapolis (where the anti-ICE protests are happening right now) is right about where the bottom of the "R" in "TREE" is on this map.

Total guess, but: Lake effect probably prevents huge temperature swings further east (the great lakes are GIGANTIC sinks of energy), and there are mountains to the west, I believe. The problem is the flat area pictured.

Also, the shape of the polar vortex wind mass isn't uniform, so it likely dips further south in that region than others (in part due to the barriers described above)

For native animals? Probably not that many, as they are adapted to the fact that it gets very cold.

Stray cats and dogs? Probably quite a few.

Didn't expect such damage

I naively thought it was some exploding in beauty kind of thing

If it takes trees exploding and not ... everything else that tips you off, you're either a fool or not paying attention, or both.