Several months after the event, the tornadoes that were determined earlier are officially certified in NWS Storm Data. The preliminary reports, or what is outlined in step one above, are what is immediately available and frequently make it into summaries and articles in the following days.
However, it is important to remember that the preliminary tornado numbers can vary quite a bit from the actual number of tornadoes that occurred, depending on how Local Storm Reports were entered during the event. The bottom line is that preliminary severe weather reports are a great resource, but like all great resources be sure to use it wisely!
On May 20, 2013, a mile-wide tornado ripped through parts of the Oklahoma City region, claiming 24 lives and damaging or destroying hundreds of schools, businesses, hospitals, and homes. Often times these stats will arrive within a day of the outbreak ending, and they are almost always based on preliminary information. The tornadoes and associated statistics that are put into Storm Data are the basis for the official US tornado and severe weather record. The reports are conveniently collected on a wonderful website database managed by the Storm Prediction Center.
One tornado can be reported by multiple individuals, or a longer-tracked tornado can produce damage in multiple communities – resulting in several reports.

This means that on average there were approximately 87% as many confirmed tornadoes when compared to preliminary reports, or a general over-counting. The problem of over-counting can particularly be exacerbated in significant tornado outbreaks, as that is usually when longer-tracked tornadoes occur – the type of tornadoes that can have numerous reports along their track. Many violent, long-tracked tornadoes occurred that day, each affecting multiple communities along their damage path. President Barack Obama declared a federal disaster in five Oklahoma counties and marked the tornado as one of the most destructive in US history.
The main purpose is to transmit information about damage and severe weather occurrences, rather than an exact tabulation of the number of tornadoes. The maps and preliminary counts on that website give a good sense as to the overall magnitude of the event and the location of the greatest reports. Others have noted this trend, as well as a general inflation in the number of preliminary tornado reports as time goes on.
Those also happen to be the cases when there tends to be greater interest in totaling up the number of tornadoes and putting things in a historical perspective. In total, 292 preliminary tornado reports were received from 8 AM EDT on April 27th to 8 AM EDT the following day.

As a result, the May 20 tornado has paved a very difficult recovery and rebuilding road that will undoubtedly impact local business owners of all stripes for months to come. In order to understand the difference between tornado reports and actual tornadoes, you need to be familiar with the process of how a tornado gets confirmed by the National Weather Service (NWS). In other words, it seems more likely that inaccurate tornado figures will get cited in the biggest events. However, there were 173 confirmed tornadoes in that same time period – still a significant number but only 59% of the preliminary figure. 23 of the tornadoes had at least a 25 mile long path, with 7 of those tracking at least 50 miles.

Risk assessment management sheet
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  1. 16.05.2014 at 21:26:49

    The worst comes team of buddies) and try to make it around the Escape Route.

    Author: rumy22
  2. 16.05.2014 at 18:51:41

    Reluctant to implement essential grid shut down actions on warning for significant.

    Author: ANTIXRIST