The sleet and snow that fell on January 15 2013 in White County Arkansas was not normal. Background levels in this area are 35cpm. The sleet and snow was showing an alert level above 100cpm. The high levels only lasted about 24 hours indicating a short half life of the hot particles.
This kind of exposure can reduce the immune system and may be the cause for recent spikes in flu and illness in this area and others. We can only assume because the event was short lived is why they are not warning parents to keep there children out of this unsafe wintery mix. Not creating panic or concern seems to be more important than public safety.
Why warn parents exposure to the snow and sleet is equal to flying at 30000 feet or exposure levels for nuclear plant workers right?