It is irrelevant whatever type of snow was there. As per procedures there is no distinction between wet and dry snow. At least as per Boeing/Airbus procedures. Must be removed regardless and this is a correct methodology, because it is consistent and simple to remember for crews, rather then to define what type of snow you have, which will inevitably involve subjectivity and errors. Just look at our example - aeroflot officials claim it "was blown-off instantly" implying it was a dry snow, while it was WET (check METARs I supplied in similar thread in Tech Log) and was not blown off instantly at all, but in patches and only partially by the time of rotation.
If you are asking out of curiosity though, check meteorology handbooks for generally accepted definitions.