Severe Weather Alert

Understanding the behavior of severe spring and summer storms can greatly assist student transportation emergency planning and training. Understanding the behavior of severe spring and summer storms can greatly assist student transportation emergency planning and training.

Severe thunderstorm and tornado events are most common in the spring, and there are major differences between how student transporters should handle them compared to winter weather. But both conditions have something in common: We don’t want school buses loaded with students stuck in either of these elements.

During severe winter weather, especially when there is a lot of ice on the roads, we’d prefer the students remain safe and warm at home. But that can all change when a severe thunderstorm or, worse, a tornado strikes at a moment’s notice. Many homes as well as school sites located within Tornado Alley have shelters where students and others can huddle for safety. But that doesn’t mean they are 100-percent safe there. And, as we saw in late February when an uncharacteristically early tornado hit the Eastern Seaboard, many areas not accustomed to dealing with these storms can be caught unaware and unprepared. 

If severe weather threatens during the middle of the school day, we have some time for hopefully the storm to pass before worrying about transporting the students back home. And most of these tornado situations are over fairly quickly. Keep in mind that although tornadoes are most common in the late spring in the Great Plains and Midwest, tornadoes have occurred in all 50 states and in every month. 

Thunderstorms, which can produce severe weather including tornadoes, develop quickly, sometimes in the matter of minutes, and they can move rapidly at speeds of up to 50 mph. They are relatively small and the area that would actually be affected by extreme weather is usually less than a mile wide although sometimes several miles long. Thunderstorms cannot be forecast ahead of time, not if we’re talking about exact location and time. The best meteorologists can do before the event is to say that an area has the potential for storm development. It is only after the storms develop that we can track them on radar and be more precise in terms of when and where damage may occur. And this only gives a short warning, typically less than an hour. But these storms tend to pass quickly and things can, hopefully, get back to normal.

When meteorologists talk about “severe weather,” they are typically referring to “severe thunderstorms” or tornadoes. A “severe thunderstorm” is one that can produce strong, straight-line winds of up to 100 mph and can include large hail. There is seldom specific warning of lightning, which by definition occurs in all thunderstorms. Flash flooding that can result from thunderstorms is a separate warning, altogether. Tornadoes, which are produced by some severe thunderstorms, are also warned separately because of the great safety threat they pose with wind speeds that can exceed 200 mph. 

If you want to keep track of the possibility of severe weather in your area, the Storm Prediction Center (SPC) at the National Weather Service (NWS) is the place to go (http://www.spc.noaa.gov/). The Convective Outlook shows the possibility of severe storms that are up to three days out, and there is even a more general outlook out to eight days. Closer to the actual event, the SPC can issue either a severe thunderstorm or tornado watch, if conditions warrant. This means atmospheric conditions favor the development of such storms. (There are specific factors which indicate the possibility of tornadoes beyond those that generate severe thunderstorms.) A watch is typically issued hours before the start of the event. A large area is covered in a “watch box,” usually 25,000 square miles. Only a tiny fraction of that area would actually be affected by severe weather, but this is the best we can predict. If the SPC points to a particularly dangerous situation, that infers a high risk of very intense thunderstorms or tornadoes. For the general public, a watch means simply to pay attention to the weather and be prepared if a severe weather situation develops.

Severe thunderstorm or tornado warnings are issued by your local NWS Office. They are based either on actual reports of the severe weather or indications of such via Doppler radar. Warnings are generally issued for a much smaller area, such as a county or two, or even part of a county. Locations within the warning area can expect to be affected within an hour or less. This means take cover

These events can pose a great challenge to those in charge of student transportation. Often, transportation departments will work closely with school safety personnel. As is the case for any emergency situation, advance planning is essential. For sections of the country prone to this type of severe weather, it is imperative that the students and school staff have a safe place to go when a warning is given. Chief Ron Brown, director of school safety for the Topeka, Kansas, Public Schools, and Dave Pettit, director of transportation for the Joplin Schools in Missouri, noted that FEMA has set requirements for tornado shelters. For school buses, drivers need to know the closest shelters along their routes. 

With these rapidly developing weather situations, especially if a watch has been issued for your area, constant monitoring of weather conditions is essential. Your local NWS Office is your best source of information. Go online to http://www.weather.gov/ and click your location on the U.S. map to connect to your local NWS office. Weather radar is the best tool to follow thunderstorm development and movement. Doppler radar, which detects rotation in a thunderstorm and has been widely used since the 1980s, often gives the first indications of strong winds, straight line or tornadic. Ian Wolfe, safety director for the Oklahoma City Public Schools, stated that his school system can close for the day if the area falls under a Tornado Watch and the situation is noted as being extremely dangerous. Some school systems have a similar policy, others prefer to monitor the situation while remaining open.

Many transportation and safety directors have a NOAA Weather Radio with an alarm feature. If a severe thunderstorm or tornado warning is issued by the NWS, an alarm will be sounded. For a severe thunderstorm warning, an even higher level of alert is called for but not necessarily evacuation to shelters unless a very definite immediate threat exists. Brown said if actual damage has been reported with the storm, then action will be taken by schools in the storm’s path.

Tornado warnings represent an even greater threat. For many school districts, a tornado warning means that all schools go into immediate “lockdown.” Everyone should proceed as quickly as possible to a designated shelter. In Oklahoma City, a large school district with excellent weather resources, the district has been broken up into 16 warning zones, according to Wolfe. Evacuation to shelters can be ordered only for those schools immediately threatened. 

For transportation, no buses should leave a school or yard during a full tornado warning. If buses are en route, communication is critical during these events. In particular, bus drivers need to be informed immediately if severe weather is threatening. The standard two-way radio is typically used to convey a warning situation (cell phones could also be used in an emergency). As Pettit added, “We make sure to maintain calmness and not use words that will cause panic in our students or drivers.” If drivers receive a warning message while on the road, they then proceed to the nearest designated shelter depending on where they are on their route, not necessarily the home school. This shelter information is part of their standard training. Upon arrival, students and drivers will proceed to the shelter and stay there until the warning has expired.

The worst case scenario would be if the bus couldn’t get to a shelter in time and it encountered the extreme weather on the open road. What do you do then? There is a dichotomy of opinions. Pettit in Joplin and Scott Lane, transportation director of the Oklahoma City Schools, both recommended that the students remain on the bus. The idea is that the bus will provide more protection from flying debris, one of the greatest threats during strong wind or tornado situations as well as from hail. Buses should also be parked away from power lines and trees.

On the other hand, Margaret (Peggy) Clark, transportation manager for the Topeka Public Schools, advised evacuating the bus, noting that a direct hit by a tornado could easily roll the vehicle if not lift it entirely off the ground. This, she noted, is particularly threatening situation if seat belts are not available. Officially, the NWS recommends leaving the bus. It recommends that passengers lay flat on the ground and protect their head. Often you hear about taking refuge in a ditch or other low-lying area. Extreme caution must be used in these cases, since these areas could easily fill with water produced by excessive storm rainfall. 

Clark also cited after-school activities as being problematic during severe weather situations. She pointed out that activities such as sports events can be cancelled, even if the area is only under a severe weather watch. A similar policy is enforced in Oklahoma City, according to Scott Lane. Brown said he is concerned that participants in these activities may not be typical bus riders and may not know proper safety procedures in these situations.

As Clark summed up regarding severe weather events, “Follow the rules you have laid out. These are dangerous situations.” 

Last modified onTuesday, 17 May 2016 09:56