Boulders serve the purpose of slowing or preventing access to an area. They are classified into two categories: Volcano Boulders and Snow Cave Boulders, which can be pushed using loose items, potentially allowing players to move them out of the way without the use of Dynamite.
The volcano boulders spawn when a player enters the volcano. They roll out of the boulder cave before coming crashing down the path, sending anything in their way flying.
They cannot damage a player themselves, but they can send players, as well as vehicles, into the lava. It is best to avoid them for this reason.
They have a faint red glow that is only visible by the entrance to the volcano.
Snow Cave Boulders
Snow Cave Boulders are large, grey, rectangular rocks that spawn within the Snow Cave, both during Server Initialization and whenever the game detects that a majority of them have been missing for a short period of time.
These boulders tend to be at least 6 units wide on all sides. When they spawn, they come crashing out of the cave and into the passage separating the Taiga from the Main Biome, blocking the passage and preventing access to the Taiga from the Main Biome or vice versa.
The passage can be unblocked by exploding the boulders with a piece of dynamite. One must set the dynamite on the ground and run away to not be killed in the blast, then quickly drive or walk through the passage before the rocks are cleaned up and respawn.
Volcano Boulders may occasionally fail to be destroyed upon hitting the lava at the bottom of the Volcano, causing them to pile up at the volcano's entrance and hinder entry for a time. Some of them may even get flung and land on the Main Biome.
Snow Cave Boulders may occasionally fail to respawn correctly, preventing them from re-blocking the passage separating the Taiga from the Main Biome after it has been unblocked once with Dynamite. Also, boulders flung away from the passage by Dynamite may fail to disappear if they collide with a tree shortly after detonation. Snow Cave Boulders can also disappear without the use of dynamite if they are moved using glitches.