Derecho Storm

A derecho is a widespread, long-lived wind storm that is associated with a band of rapidly moving showers or thunderstorms. Rather than a tornado that circulates and spirals, a derecho creates a long straight “wall” of clouds that can pick up sand or soil. A derecho can be  observed when the wet air of a thunderstorm meets the drier air surrounding it causing the water in the storm clouds to evaporate.  Evaporation cools the air causing it to become more dense. Dense air sinks and creates a long downburst of wind. Derechos can be  common in Iowa because of the rapid changes in weather and wind speed/ direction.

Driving Question

• What causes a derecho?

Probing Questions

• How might water evaporation affect air mass?
• What tools do you think can be used to collect data that is beneficial for predicting a storm or derecho?
• Why might people want to try and predict storms?

Classroom Suggestions

• Show a video of a derecho as an ‘attention grabber’ in the beginning (either ours or a more “professional” one the teacher finds online).  Students would record what they notice as well as what they wonder about the possible cause of this storm. 
• Hot/cold water density experiment: visual of how the warm and cold air masses interact. 
• Create a barometer: measures air pressure, drop in air pressure when derecho storms are coming.

Relevant Related Resources

What is a Derecho? | Scijinks: Helpful for understanding what exactly a  derecho is and how it forms. It is explained in simple enough terms that middle schoolers should be able to understand. 
Derecho | weather.gov: A more in depth explanation that gives many helpful visuals and graphs to help students understand how derechos form and move. It also helps students understand where/when derechos are likely to happen.​​​​​​​
Derecho | Britannica: This resource does not have much new  information, but the visual showing the  evolution of a gust front makes it very easy to understand and visualize. ​​​​​​​
About Derechos | NOAA: Gives facts about derechos and a more  detailed explanation. It would be helpful to  build background knowledge for teachers!