Ed. Note — Adam Jaquet, director of the City of Galva Emergency Services and Disaster Agency (ESDA), wrote this column for Severe Weather Awareness Week in Illinois.

Ed. Note — Adam Jaquet, director of the City of Galva Emergency Services and Disaster Agency (ESDA), wrote this column for Severe Weather Awareness Week in Illinois.

 

March 4-11 marks 2018 Severe Weather Awareness Week in Illinois. Both Galva schools conducted their annual tornado/severe weather drills on Tuesday morning with the regular monthly test of the storm sirens. And you should also do a drill in your homes and businesses. Talk about what you do in the event of a severe storm. Where is your safe location? Hint — it is not standing outside on the porch, in the doorway with the door cracked and your cell phone shooting video, or looking out the window. Severe weather is deadly serious. 

 

Watches and Warnings

There are two primary products that are issued by the National Weather Service (NWS) of concern for the Galva area (at least in reference to this article about thunderstorms and tornados). A Watch is a product of the NWS Storm Prediction Center (SPC) in Norman, Okla. The forecasters in the SPC analyze conditions across the entire United States every day for the ingredients of severe weather. 

They will consult with local forecast offices (for Galva it is Davenport, Iowa, and Lincoln) and decide if conditions are favorable for severe weather to occur. 

In this instance, a Watchwill be issued. A Watch usually encompasses several counties, and even multiple states, and means that severe weather may occur within that area in the time frame defined in the Watch. The time frame is usually 4-6 hours.

So what do you do when a WATCH is issued? The first thing is to listen to the type of watch, the area covered and possible time of arrival. If a Severe Thunderstorm Watch is issued, it means the forecasters expect storms to develop that will produce high winds and/or damaging hail. 

If a Tornado Watch is issued, it means forecasters expect storms to develop that may produce tornadoes. Once you learn what kind of Watch has been issued, and your area is included in the watch, you should be paying attention to the weather, either through traditional media outlets (local television and radio stations) or on your NOAA Weather Radio. 

A Watch shouldn’t prevent you from engaging in most regular activities. However, it means you need to be extra aware that severe weather may occur and you should have a plan ready to execute if conditions actually become severe.

The second type of product the NWS issues is a Warning. Warnings are issued by the local NWS forecast office and means that severe conditions are occurring NOW or are imminent. 

If you are in a warning, you should take cover IMMEDIATELY! Warnings are issued in a much more focused area. Usually they will only encompass part of a single county or portions of two or three adjacent counties. Warnings are drawn in the direct path of an occurring severe condition. When a warning is issued by the NWS, it is based on either radar data collected by the forecast office, or direct reports from Emergency Managers, Trained Spotters and Law Enforcement.

A Warning can be issued, even if a Watch was not issued previously. 

 

Severe Thunderstorm 

vs. Tornado

What’s the difference between a Severe Thunderstorm and a Tornado? By NWS definition, a Severe Thunderstorm includes either 58 mile-per-hour winds, or hail one inch in diameter or larger. While lightning is visually impressive, the amount or intensity of lighting in a thunderstorm has no bearing on whether it is classified as “severe” and thus, will not prompt a warning. However, lightning is still dangerous. If you see lightning or hear thunder, seek shelter indoors. Lightning can strike from a long distance away, even if there are no clouds directly overhead. Do not hide under any vertical objects, like trees, because they will attract lightning.

A tornado is a violently rotating column of air in contact with the ground and the cloud base. Contrary to some perceptions, a tornado is not always visible. It is well documented that a tornado can exist and never actually have the visible “funnel” shape. There is also a difference between a tornado and a funnel cloud. A funnel cloud is a violently rotating column of air, but it is not in contact with the ground. It may become a tornado. Or a tornado may become a funnel cloud. Or it may go back and forth between the two (May 1998 Galva tornado). 

 

Sirens

Galva has four warning siren locations — Galva Elementary and High School, Fire/Police Department (old City Hall), City Maintenance Yard and Park District. 

A fifth siren location is currently being installed in Prairie Ridge Subdivision and should be fully operational in the next few weeks. If the sirens are activated for severe weather, the sound will be a long continuous blast that lasts for three minutes. Depending on the situation, they may be reactivated for additional durations. 

There is never an “all clear” sounded. There is also a fire siren residents may hear. This siren is activated by the Fire Department. It only sounds from the siren on the Fire/Police Department building and will be a wave or pulsing sound getting louder and then fading down, then back louder, and down again.

 

When are Sirens Activated?

The sirens in Galva are controlled locally by ESDA. Sirens are activated for the same reasons the NWS would issue a warning — Severe Thunderstorms with hail of one inch diameter or greater, winds in excess of 58 mph, or a tornado (occurring or likely to occur). The decision to activate the sirens is made by the ESDA director, or their designated assistants. 

The director uses information available from the local trained spotters, NWS and other weather data sources. The Emergency Operation Center for the city has multiple computers monitoring radar, watch and warning updates, storm reports and local media. 

Galva may be placed under a Warning by the NWS, but the sirens are not activated. This is not because the director disagrees with the warning, but because sometimes warnings are issued based on radar data alone. A radar scan is reading data 1,000+ feet in the air. Those may not be the same observed conditions on the ground. 

Does this mean you defer to the sirens over the warning? ABSOLUTELY NOT! Take every Warning seriously and seek immediate safe shelter. The sirens are more like a redundant warning system. It is also possible that the sirens will be activated before a warning issued by the NWS (May 17, 2017 — Galva was never actually under a warning, but there was a tornado just west of town). 

 

What to do Now?

So what do you do now? First, develop a home severe weather emergency plan (lots of online resources through NWS, and other government agencies). Second review the plan with everyone in the household and practice the response. Drills in normal conditions help alleviate problems when your adrenaline kicks in or panic starts. Third, get a NOAA Weather Radio that has battery capabilities. This is a direct broadcast from the NWS, and can be set so it will come on automatically if a Watch or Warning is issued. Fourth, be weather aware. Pay attention to conditions and forecasts. And if a Watch or Warning is issued, put your plan into action. 

 

Any questions?

If you have questions, need further information or would like to volunteer as a Storm Spotter with ESDA, contact Adam Jaquet at (309) 854-3180 or adam_mm32@yahoo.com.