I found this on runblog.com:
"In the normal way the Diamond League programme was preceded by a normal schedule of national events. In an abnormal way, one of the events was the Junior Norwegian Snowball Championship. Yes, children (11-13 years old) throw snowballs and measure the distance to where they land. RunBlogRun commends this innovation but isn't it a winter sport if it involves snow? For the record, Eric Becklund is the 2017 Junior Norwegian Snowball Championship with a throw of 54.79 meters. In third place and first female was Malene Storoygard with 46.19 meters."
So are the snowballs standardized?