THE A T M O S P H E R I C R E S E R V O I R Examining the Atmosphere and Atmospheric Resource Management “Winter Weather Review”

By Mark D. Schneider or significant ice accumulations, usually at least 24 to 36 hours in Last winter, unseasonably advance. The criteria for this watch cold temperatures and blowing can vary from place to place. snow created hazardous weather conditions across our state. In Winter Storm Warning – fact, eastern North Dakota tied Issued by the NWS when a winter storm is producing or is forecast to 1996-97 for the most blizzards Winter on the Missouri River. in a season. Thomas Grafenauer, produce heavy snow or significant a lead forecaster with the Grand of three hours.” This means that ice accumulations. The criteria for Forks National Weather Service new snow doesn’t have to be falling this warning can vary from place to (NWS) Forecast Office stated that, during a blizzard when existing place. “The ten blizzards that occurred snowfall being blown by strong in our county warning area last winds reduces visibilities below Winter Weather Advisory winter didn’t contain the record one-quarter mile. It’s important – Issued by the NWS when a snowfalls that we witnessed during to note that blizzard conditions low-pressure system produces a the 1996-97 season; however, they may also occur outside of blizzard combination of winter weather still had considerable impacts on warnings either because of their (snow, freezing rain, sleet, etc.) that our roadways and utilities due to the short durations or because they’re presents a hazard, but does not meet cold temperatures and winds.” occurring in areas that don’t have warning criteria. The NWS now weather recording instruments. uses winter weather advisories in Western and central North place of snow advisories. Dakota received the lion’s share of According to the American strong to severe winds during the Meteorological Society Glossary of Now you know some of the month of January. In fact, Bismarck Meteorology, earlier definitions of a differences between the common and Garrison both had 16 days blizzard included a condition of low watch, advisory and warning during the month when 40 mile per temperatures. If air temperatures products that the NWS issues hour or greater wind gusts were were 20 degrees Fahrenheit or during the winter season. It’s the recorded. Minot recorded 15 days lower, then that used to qualify mission of the NWS to provide of 40 mile per hour or greater winds under blizzard criteria. When the warnings and advisories in the and Hettinger, Jamestown, and temperatures dropped to 10 degrees interest of public safety and the Williston all recorded 14 days. On Fahrenheit or lower, then “severe nation’s economy. These products January 16, a 75 mile per hour wind blizzard” criteria were reached. have definitely helped protect the gust roared through Garrison! The current definition of a blizzard livelihood of North Dakotans, doesn’t include temperature as a especially during our eventful The NWS issues blizzard criterion though. winter seasons. warnings for “winter storms with sustained or frequent winds Lets review the definitions of of 35 miles per hour or higher other winter weather products from Atmospheric Resource Board with considerable falling and/ the NWS: North Dakota State Water Commission or blowing snow that frequently 900 East Boulevard, Bismarck, ND 58505 reduces visibility to one-quarter of Winter Storm Watch – This (701) 328-2788 • http://swc.nd.gov a mile or less. These conditions are product is issued by the NWS when ND Weather Modification Association expected to prevail for a minimum there is a potential for heavy snow PO Box 2599, Bismarck, ND 58502 (701) 223-4232

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