Forecasters knew storms were likely the afternoon of August 28th, but none had anticipated a major storm to move through northern Illinois. Storms started to develop along the Wisconsin/Illinois border around the noon hour and began to track south/southeast. As they did, brief tornadoes touched down around Pecatonica and Seward at 1:42pm causing minor damage. As the storms continued to move southeast, the atmosphere began to grow increasingly unstable. Supercells produced damaging winds along with large hail through portions of DeKalb and Kane counties. It was there that storm chaser Paul Sirvatka ( storm chaser and professor at the College of DuPage) observed the storm as it moved out of the DeKalb area and towards Sugar Grove. Instability and wind shear began to increase and produced four tornadoes in southern Kane county before it moved through Plainfield and Crest Hill producing an F5/EF5 tornado. Sadly, it wasn't until the tornado dissipated near Joliet that the first report came into the National Weather Service.
Why was that? The storm chasers fell behind the storm and were never able to catch up with it. Since the storm was rain-wrapped they were not able to see it. As a result, there were no tornado watches or warnings. Even as the storm was moving into Plainfield residents still had no idea until it hit.
So much in the field of meteorology has changed over the past 20 years. What was once a sparse network of spotters and radars has quickly bloomed to over 3000 people taking part in spotter training courses and a dense population of doppler radars. The Weather Service in 1990 was using 1974 radar technology which was based on 1957 radar design. Warning forecasters could only view the base radar on a TV monitor while what the radar operators could see had to be relayed through summary products or via phone. There was no way for forecasters to determine the presence of strong rotation which is indicative of a tornado. Now we have state of the art Doppler radar technology (which will be upgraded even further come 2011). It is of higher resolution, has more power, produces products for analysis of precipitation and can also detect wind motion within a storm. Communication has also improved between forecasters and emergency managers, the media and the public. NOAA weather radio transmitters have also increased to provide continuous forecasts. Just our general knowledge of storm formation has also improved through extensive research and training over the past several years! While there is still so much more to learn within meteorology, we have come very far since 1990!
Great info! Thanks for sharing. I have 2 comments:
ReplyDelete1. (regarding part 1 of this post) - I lived in Bolingbrook at the time, about 8 miles from part of the storm path. I was young but I remember that day. We only had a few trees down from strong winds, but in the upcoming weeks my parents took me into Plainfield to see the damage. Very devastating. I didn't realize at the time how close we were to such a violent tornado.
2. While communication about severe weather has improved, there is still lots of work to be done. And unfortunately, the institutional memory of the storm and the lessons learned, I fear, are fading. A couple years ago a friend of mine worked in a Plainfield school. It was after regular hours, and there were some storms in the area, but nothing too severe. The tornado sirens went off and noone knew what to do. The only weather radio in the building was locked in the main office. Kids were brought into the gym, then out of the gym into an exposed hallway. My friend, not knowing what to do, called me to ask for a weather update. Luckily there were no warnings out and the alarm had been falsely issued, but still...EVERYONE should know what to do! Just an eye opener that continued education is desperately needed. You can't tell people enough times what to do during an emergency. (FYI - that school now has several weather radios!)