Monthly Archives: April, 2011

Jumping To Conclusions

Yesterday, April 22, 2011, a tornado moved through parts of the St. Louis metro. There’s a substantial amount of damage done to all kinds of structures including the St. Louis Lambert International Airport. All day long there have been ‘sound bites’ and tweets proclaiming the entire tornadic event as EF-4.

Wrong.

Read the following…

PUBLIC INFORMATION STATEMENT
NATIONAL WEATHER SERVICE ST LOUIS MO
305 PM CDT SAT APR 23 2011

…SURVEY TEAM RATE DAMAGE IN BRIDGETON AS EF4…

THE NATIONAL WEATHER SERVICE DAMAGE SURVEY TEAM IN NORTH ST LOUIS
COUNTY HAS FOUND EF4 DAMAGE IN THE BRIDGETON AREA…NEAR OLD ST
CHARLES ROCK ROAD AND HARMON ESTATES.

EF4 DAMAGE INDICATES WINDS OF 166 TO 200 MPH.

PLEASE NOTE THAT THIS IS STILL A PRELIMINARY REPORT…SO INFORMATION
MAY CHANGE AND BE UPDATED AS SURVEY TEAMS CONTINUE THEIR WORK.

SURVEY TEAMS HAVE NOT YET REACH LAMBERT FIELD…SO NO DAMAGE RATING
IS AVAILABLE FOR THE AIRPORT AT THIS TIME.

As it clearly states, the EF-4 rating has been applied only to a small part of the tornado’s damage path. There are countless miles yet to be surveyed. There are countless trips made with fixed wing aircraft and helicopters with meteorologists and structural engineers aboard flying over the damage path…again and again and again. The airport has not been surveyed. Most importantly, all of the information is preliminary aka subject to change.

Damage surveys are very labor intensive and time consuming. Meteorologists must find extra time away from their normal forecasting, analysis, and research to take the time to travel the entire length of a tornado path. All the while, they can’t neglect the duties that are the primary purpose of operational meteorology.
Case in point; the Tulsa NWS is still compiling data on the tornadoes that occurred in the Tulsa forecast area on April 14, 2011. To take that much time analyzing tornado paths, verifying reports of damage, utilizing the EF-scale is completely normal and a sign of good science. Unfortunately, media and social media grabs onto the first EF-scale rating and broadcasts (or tweets) it as loud as they can.

Good science takes time. It will be many days before the damage around St. Louis is properly surveyed, reports written, data doubled checked for accuracy, and a final report written. The most important thing for people who were not affected by the recent severe weather is to pay attention to the weather conditions they’re exposed to and prepare properly to implement safety precautions if necessary.

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A Spring Change For April

This image from the Oklahoma Mesonet shows a drastic change in both temperature and wind direction as a cold front was making its way across the state. The observation was taken at 2020 on 2 April 2011. The approximate locations of the cold front (blue) and dry line (red) are marked. It’s easy to see the differences between the two air masses.
Drastic changes in mesoscale conditions are frequent in the spring throughout the Great Plains and this instance was no exception.

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