Tradition says that this is not true but honestly I have no real experience except I have done the calculation for our roof. According to our local building standards at 60⁰ you basically have zero snow load, I am not sure what angle a shallow angle roof is but 30⁰ is max load. 6kN/m² is a lot of extra strength.

In Finland, where you can easily get 30cm or more snow, all roofs are required to stand 100-300kg/m2 by law and most roofs are less than 30 degrees (e.g. 1:2 ratio).

A-frame or even 45degree angle roofs are very rare.

The only limit to how strong you can make a roof is really money. If you space joists or trusses half as far apart you will about double the max snow load.