Rating Snowstorms Based on Travel Impacts Ernie Ostuno National Weather Service, GRR

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<ul><li> Slide 1 </li> <li> Rating Snowstorms Based on Travel Impacts Ernie Ostuno National Weather Service, GRR </li> <li> Slide 2 </li> <li> Storm Impact: Travel Conditions Recent survey found (not surprisingly) that travel impacts were the leading cause of people altering their normal routines during snowstorms </li> <li> Slide 3 </li> <li> Two Methods of Ranking Storms Pre-Storm: Pre-Storm: Saffir/Simpson scale: damage potential Post-Storm: Post-Storm: EF scale: damage assessment </li> <li> Slide 4 </li> <li> Winter Storms: Criteria vs. Impact NWS warning criteria based on amount and rate of snow NWS warning criteria based on amount and rate of snow Impact: primarily the effect on travel conditions, which we dont explicitly forecast Impact: primarily the effect on travel conditions, which we dont explicitly forecast Zielinski (2002), Grumm and Hart (2001) rated winter storms based on meteorology Zielinski (2002), Grumm and Hart (2001) rated winter storms based on meteorology Kocin and Ucellini (2004) rated winter storms based on impacts Kocin and Ucellini (2004) rated winter storms based on impacts The impacts did not include taking into account some important variables The impacts did not include taking into account some important variables </li> <li> Slide 5 </li> <li> Northeast Storms Severity Index Based on amount of snow that affects the greatest area/most population Based on amount of snow that affects the greatest area/most population Somewhat analogous to the EF-scale; tornado will likely get a higher rating if it hits a city Somewhat analogous to the EF-scale; tornado will likely get a higher rating if it hits a city Ranks 11-12 Feb 1983 higher than 6-7 Feb 1978 Ranks 11-12 Feb 1983 higher than 6-7 Feb 1978 Not accounted for: Timing, winds, temperatures, local severity Not accounted for: Timing, winds, temperatures, local severity </li> <li> Slide 6 </li> <li> Variables Affecting Travel Impacts Snow: Amount, Rate, Timing Snow: Amount, Rate, Timing Wind: Speed and Duration Wind: Speed and Duration Temperature: Hypothermia, Road Salt Temperature: Hypothermia, Road Salt Icing: Freezing rain, rain to snow Icing: Freezing rain, rain to snow </li> <li> Slide 7 </li> <li> Ranking Historic Northeast Snowstorms February 6-7, 1978 February 6-7, 1978 January 7-8, 1996 January 7-8, 1996 February 11-12, 1983 and 2006 February 11-12, 1983 and 2006 February 16-17, 2003 February 16-17, 2003 April 1, 1997 and April 6, 1982 April 1, 1997 and April 6, 1982 Ranking Factors : Amount of snow, winds, persistence of deep snow Societal impacts to account for: Economic disruption, travel bans Discussion point: which is more important, snow amount or wind? Drifting snow and snowfall rates are important factors in affecting travel, as well as timing What makes a storm memorable enough to mark anniversaries of it? </li> <li> Slide 8 </li> <li> Rankings by Snow, Wind* Snow17.7200615.5198315.4199615.1197813.12003 *Average of BDR and BDL snow totals and peak winds ** Top ranking for each category is given 5 points, next highest given 4 points, etc., then added together. Wind is given a weighting factor of 1.5 Wind401978371996362006332003281983 Rank points** 20069.519789.51996919835.520034 </li> <li> Slide 9 </li> <li> A Look at One Possibly Important Variable: Snow Depth Following some of the Big Storms Snow depth in inches (y-axis) measured each day after the storm (x-axis) Post-storm assessment ranking: 10 inches or more on the ground 5 days after = 1 point 10 inches or more on the ground 10 days after = 2 points </li> <li> Slide 10 </li> <li> Final Ranking Rank points 197811.5199611200610.519836.520034 </li> <li> Slide 11 </li> <li> The Old 1 to 5 Scale Wind (mph)Snow (In)Temp (F) Wind (mph)Snow (In)Temp (F) &gt;40 5&gt;12 5 40 5&gt;12 5 </li></ul>