The big storm that swept through the east coast last week was called a Derecho-what exactly is that...and can that happen here?
The term 'derecho' comes from a Spanish word meaning 'direct' or 'straight ahead'. That refers to strong winds spreading out ahead of a band of thunderstorms. Those winds can range from 57 to more than 100 mph. Such a band of thunderstorms is often curved, which is why meteorologists call them 'bow echoes'. Such bow echoes can range from 40 to 250 miles in length. While bow echoes are most common east of the Rockies, we can get 'straight line winds' from a thunderstorm or small squall line that can cause damage; in fact, such straight line winds knocked down trees in the Arlington area recently.