The equatorial ridge planet!
I invented this fast spinning planet for your question about the all-Mediterranean world. But I cannot find that question - you must have deleted it. I wonder why? I thought it was a fine one.
In any case: same principle here but colder. The planet spins fast and so is flattened with a high altitude equatorial bulge. The whole planet is colder than the Mediterranean version I would have liked to link up here. The only biome is the tundra biome, a term which I think is more specific to what you are looking for at high altitude on mountains.
Tundra is a region found in the coldest places on earth. They are of
two types: the arctic tundra and the alpine tundra. The Alpine tundra
is located on high mountain regions in the world, for instance, the
Swiss Alps. As opposed to the Arctic Tundra, the Alpine Tundra are
found away from the pole regions. The word ‘Alpine’ is derived from
the Alps which are high mountains that are found in Central Europe.
The characteristic of the Alpine is similar to polar tundra in that it
has no trees, has annual temperatures that are recorded to be very
low, and most animals migrate to these regions only during the
productive summer periods.
Places which would be warm because of latitude are not warm, because of altitude. The tundra at higher latitudes just continues on to the lower latitudes and higher elevations.
Most of the water is locked up in polar glaciers. Precipitation comes from glacial melt in the summer.