Answer: Snow and ice can break any type of plant, evergreen or deciduous, tree or shrub, if the conditions are severe enough. Broadleafed evergreens with a broader surface area tend to hold more snow more easily and thus would be more likely to be subjected to damage as a result. On the other hand, the plants are generally quite sturdy and thus do not usually break unless the snow is both very heavy and quite thick, or if winds are very strong during the storm.
But yes, typically it is recommended to gently whisk away the snow before it accumulates into a layer that is heavy enough to cause severe bending and possibly then cause breakage. Wet snow is much heavier than powder, so the type of snow is probably as important as the visible volume.
In a wet snow, this could require venturing out into the storm periodically to gently brush or shake off the snow before it makes such a thick layer -- for example, if ten inches are predicted this is probably a very good idea. You can use your arm or a broom to brush and jiggle off the accumulation if you notice the plants are being weighed down to an extreme. In my experience ice storms tend to do at least as much damage as a heavy snow, and sadly there is little that can be done to prevent ice damage.
If the plants are weighted down a bit and you are worried about breakage in ensuing winds, or additional accumulation is expected prior to this batch melthing, or if now an ice storm is one the way, you can still do it now as long as the snow has not been iced too firmly into place. It would not hurt the plants to remove it. On the other hand, some people find a light to moderate amount of snow layered over the different evergreen plants to be a decorative feature in the winter landscape.
I hope this answers your question.
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