{"id":2356,"date":"2009-02-13T17:13:53","date_gmt":"2009-02-13T22:13:53","guid":{"rendered":"http:\/\/www.norman.noaa.gov\/?p=915"},"modified":"2018-07-27T14:26:34","modified_gmt":"2018-07-27T19:26:34","slug":"the-rarity-of-the-oklahoma-tornadoes-of-10-feb-revisited","status":"publish","type":"post","link":"https:\/\/inside.nssl.noaa.gov\/nsslnews\/2009\/02\/the-rarity-of-the-oklahoma-tornadoes-of-10-feb-revisited\/","title":{"rendered":"The rarity of the Oklahoma tornadoes of 10 Feb revisited"},"content":{"rendered":"

One of the questions we get asked a lot about significant tornado events boils down to “How unusual was this?”\u00a0 The answer is, “That depends.”\u00a0 It depends on exactly <\/em>what aspect you’re asking about.\u00c2\u00a0 Sometimes, it’s very easy to quantify.\u00a0 Other times, it’s not.\u00a0 The case of the 10 February 2009 Oklahoma tornadoes is an excellent example of how difficult it can be to answer.\u00a0 A lot of the discussion I’ve seen has dealt with the number of tornadoes in the state of Oklahoma during the month of February.\u00a0 Although that provides a very neat and well-defined answer, it’s probably not all that relevant.\u00a0 February is a month of very strong gradients in space and time in the occurrence of tornadoes, especially in the southern Plains.\u00a0 Most of the tornadoes in Oklahoma during that month occur in the eastern part of the state and the late part of the month.<\/p>\n

To illustrate, I’ve put together a series of “postage-stamp” maps showing tornado touchdown locations by week for each of the first nine weeks of the year (e.g., 1-7 January, 8-14 January, etc.) for 1950-2007, with the Oklahoma tornadoes of this week overlaid on the 6th week’s map (5-11 February).<\/p>\n

\"Postage<\/a>
Postage stamp maps of tornado locations<\/figcaption><\/figure>\n

In general, there’s a fairly sharp boundary on the northwest side of the locations of tornadoes. For the 6th week (middle panel on the right side), the recent tornadoes are right at the edge of that boundary. Over the next three weeks, however, tornado occurrence becomes much more frequent west of where that boundary is earlier in the year. Thus, a qualitative answer to the question of rarity would be that the tornadoes would have been much more likely if they had been either a couple of weeks later or a couple of hundred miles southeast. Quantitative answers are much harder to develop.\u00a0 I’ve developed techniques in the past to look at that question, but for events like this that are right at the edges of what we’ve observed in the past, the answer you get is very sensitive to the assumptions you make.<\/p>\n

Another point that can be seen is that the 7 January 1992 tornadoes in central Nebraska (see the upper left panel) are a very long distance in space and time from anything else. They are likely to be among the rarest of tornadoes.<\/p>\n","protected":false},"excerpt":{"rendered":"

The question of how rare an event the Oklahoma tornadoes of 10 February 2009 is very difficult to answer.<\/p>\n","protected":false},"author":124,"featured_media":3613,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"_eb_attr":"","ghostkit_customizer_options":"","ghostkit_custom_css":"","ghostkit_custom_js_head":"","ghostkit_custom_js_foot":"","ghostkit_typography":"","footnotes":""},"categories":[14],"tags":[],"class_list":["post-2356","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-svr-wx"],"acf":[],"wps_subtitle":"","_links":{"self":[{"href":"https:\/\/inside.nssl.noaa.gov\/nsslnews\/wp-json\/wp\/v2\/posts\/2356","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/inside.nssl.noaa.gov\/nsslnews\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/inside.nssl.noaa.gov\/nsslnews\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/inside.nssl.noaa.gov\/nsslnews\/wp-json\/wp\/v2\/users\/124"}],"replies":[{"embeddable":true,"href":"https:\/\/inside.nssl.noaa.gov\/nsslnews\/wp-json\/wp\/v2\/comments?post=2356"}],"version-history":[{"count":1,"href":"https:\/\/inside.nssl.noaa.gov\/nsslnews\/wp-json\/wp\/v2\/posts\/2356\/revisions"}],"predecessor-version":[{"id":4885,"href":"https:\/\/inside.nssl.noaa.gov\/nsslnews\/wp-json\/wp\/v2\/posts\/2356\/revisions\/4885"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/inside.nssl.noaa.gov\/nsslnews\/wp-json\/wp\/v2\/media\/3613"}],"wp:attachment":[{"href":"https:\/\/inside.nssl.noaa.gov\/nsslnews\/wp-json\/wp\/v2\/media?parent=2356"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/inside.nssl.noaa.gov\/nsslnews\/wp-json\/wp\/v2\/categories?post=2356"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/inside.nssl.noaa.gov\/nsslnews\/wp-json\/wp\/v2\/tags?post=2356"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}