IEM Daily Feature
Thursday, 04 February 2016
Thursday, 04 February 2016
Was is a blizzard?
Posted: 04 Feb 2016 05:35 AM
The formal definition of a blizzard by the American Meteorological Society (AMS) and
National Weather Service (NWS) is somewhat vague. It requires frequent wind gust over
35 mph and frequent visibility reductions due to falling or blowing snow to less than a
quarter mile over at least a 3 hour period. There are problematic parts of that definition
including what 'frequent' means and how exactly such conditions can be observed reliably
by automated equipment and humans, who would rather not be outside for 3 hour periods
during bad weather! So was our recent storm a blizzard? The featured chart looks at the
wind speed, visibility, and time components of the blizzard definition for Mason City for the
recent event, an event from 2015 and a significant event from 2010. The chart assumes
the visibility reduction is due to snow and not fog. The highlighted ares in gray are meeting
the criteria and blue completely meet the criteria for a 3+ hour period. For the most recent
storm, only a brief period was able to meet the criteria as wind speeds were not often
above 35mph. So was the recent storm a blizzard for Mason City? It is difficult to say with
automated data, I suspect many humans would say otherwise.
Voting:
Good = 22
Bad = 12
Abstain = 9
Tags: blizzard
Voting:
Good = 22
Bad = 12
Abstain = 9
Tags: blizzard