Future EC135 / EC145  

The rest of the paragraph you quoted from the AC.....

j. Snow. In flight, dry snow is unlikely to pose a hazard with respect to icing; however, wet snow may begin to adhere to aircraft surfaces. If wet snow does begin to stick, it should then be treated as an icing encounter because ice may begin to form under this accumulation of snow. No aircraft is evaluated in the icing-certification process for this rare situation. If it occurs, the aircraft should exit the conditions as quickly as possible and declare an emergency or contact air traffic control (ATC) as necessary. Be aware that freezing drizzle can coexist with snow. If you are flying into or over areas reporting snow, it is important to understand that the presence of snow does not necessarily mean that icing conditions are not present. 

There are also numerous references in that same AC warning that flight in snow anywhere near the freezing point is a something you need to pay attention to due, exactly as discussed above.  

Referencing the IBF, the standard EC135 with no filters or the factory IBF mounted directly to the side of the engine have no limitation on snow other than they must be clear during preflight.  The FDC brand filters FMS says the following....

2.2 - FLIGHT LIMITS The limitations of the basic flight manual remain applicable. 

NOTE:Operations in falling and/or blowing snow have been demonstrated in one quarter mile or greater visibility conditions when equipped with the Engine Inlet Barrier Filter System. Minimize exposure time in ground and IGE hover operations. Snow accumulations on airframe and filter are more probable in these conditions. Exercise caution when operating in snow. Maintain visual contact with ground and any obstacles at all times.