Derechos are massive wind storms that can stretch linearly for hundreds of miles. They can include bands of showers and thunderstorms, and they can spawn tornadoes. Traditionally, for something to qualify as a “derecho,” the wind storm must extend 250 miles (~400kM), have wind gusts that equal or exceed 58mph (121 kM/h) with multiple gusts that exceed 75 mph (121 kM/h). (There are proposals to drop the wind-speed requirements but increase the length to 400 miles (650 km).)
It’s important to remember that weather and climate are different things. “Weather” refers to the day to day conditions of an area. “Climate” is the long-term pattern of weather in an area. So, Florida may have a hot tropical climate, but it might have cold weather on a particular day. A climatic drought is an overall reduction in rainfall, but a rainy day (rainy weather) can still happen during a drought.
Wikipedia lists the following years for recorded derecho events in the United States. The number of events typically ranges between one and four derechos a year. At first, it appears that more multiple-derecho year are occurring later, but the variation is large enough, and the accuracy of the earlier records is questionable enough to cast doubt on the trend. 2018 is the first year listed with six events in The United States. 2019 had one, then 2020 had six once again. There were two again in 2021, and to date (Oct 21) 2022 has had four of them.
In a late chapter, Silent Consent notes the unstable weather in the book’s universe and the frequency of derecho events and tornadoes. Climate changes have influenced the course of civilizations in the past. As climates change, so does our ability to grow crops, manage insects and diseases, and maintain population levels. The novel ask, “What kind of world will we leave to our descendants so many generations in the future.