General game information
All hazards can kill the polar bear, and all except one can be rolled up into the polar bear's snowball.
Rocks are commonly encountered hazards that when isolated require one jump to avoid. Rocks have two appearances: one with two upward points and another with three, each having a sprite with snow on it and without.
Rocks are the first encountered hazard in the game and the most common, encountered in many combinations with other hazards. When starting the game, the player will pick up isolated rocks that require a single jump to avoid, however, later on the combinations of a cluster of a rock and a tree, a cluster of three/four/five rocks, and a rock preceding a snowman's hat will be encountered.
In rocks cluster a single rock is sometimes substituted with a beaver.
Beavers require a single jump to avoid, and are identical to rocks except for occurring less often. Before a beaver is rolled up it can be seen poking up above ground, its head visible and to a lesser extent its arms. When rolled up only its head is visible.
Beavers appear less often in the game than rocks. Beavers have the same appearance combinations as rocks, except for a cluster of three/four/five beavers appearing; instead of this, sometimes in a cluster of three/four/five rocks there will be one or more beavers replacing a rock.
Main article: Penguin (Avalanche)#Roller Polar
Trees are the first hazards requiring two jumps to avoid. Trees appear with a vertical brown base with small green top and two medium sized green triangles on the top of this. Trees have two sprites: a sprite with snow on the top triangle and one without any snow.
Often first encountered after three/four rocks, trees are encountered regularly are come in many combinations, these combinations being a single tree, a cluster of two trees, three/four consecutive trees, a high flying bird that flies right before rolling into a tree, and a cluster of a single rock/beaver and a tree, this requiring the the player jump once then after a moment jump a second time.
Upon transitioning to the third snowball, a combination of three trees may come up, this combination requiring the player double jump very early.
Mooses are a seldom encountered and require a double jump to avoid. Unlike trees, mooses are only have one combination, where one moose is rolled up and requires a double jump to avoid.
Prior to be rolled up, jingling of bells are heard and a moose is seen with a startled expression trying to run away from the snowball. When rolled up, only the moose's head is seen, which is small compared to its large antlers.
Birds are the only hazards that does not need to be rolled up. Only a single bird is encountered at any time, and it is flying either high up above, towards, or in front of the Polar Bear. When a bird is flying directly towards the Polar Bear, he needs to double jump to avoid it. When a bird flies above the Polar Bear or in front of him, the player does not need to do anything since the bird cannot harm the Polar Bear this way. When a bird flying to the left notices the player, it will get shocked, speed up and fly off the screen.
In most occurrences, birds are not linked to any combinations of other hazards, though in some cases they will precede the player rolling up a tree. If a bird is included in a combination of rolled up hazards, it will occur so that it does not collide with any other hazards.
Update 1 added the bird's behaviour for flying in front of the player.
Snowmen are a unique type of hazard that are rarely ever encountered. When snowmen are seen in the path of the player, jingling of bells (different from the mooses) are heard before they are rolled up.
When rolled up the snowman will come around three time, the first time being full sized and requiring a double jump to avoid, coming around a second time as a head and hat and requiring a single jump to avoid, then lastly as just a hat preceded by either a rock or a beaver.
Interestingly, the snowman triggers a unique death animation when killing the polar bear. If the polar bear is killed by the full sized snowman, the polar bear will be thrown diagonally to the upper left corner of the screen.