By now, many people may have already heard of derecho, the fast-moving, long-lasting storm that suddenly slammed the D.C.-area Friday evening for an hour and wreaked havoc the next day for the region and beyond. Meaning “straight” in Spanish, this type of tempest started in the Midwest and accelerated speed as it headed directly toward the Mid-Atlantic region.

Friday’s derecho was an unusual one. First, this event rarely happens in the region. WJLA observed weather records and found very few occurrences in the area. The storm frequently hits the Midwest and Southern Plains between May and July.

But the record-breaking high temperatures that sizzled the region aided in the formation of the powerful 60-80 miles-per-hour winds and heavily loaded clouds with thunder and lightning, according to the Capital Weather Gang:

They often form along the northern boundary of a hot air mass, right along or just south of the jet stream – where upper level winds zip along at high speeds.

During summer, the jet stream atop a sprawling heat dome is sometimes called a “ring of fire” due to the tendency for explosive thunderstorms to form along this weather front separating hot, humid air to the south and cooler, drier air to the north.

As this stifling air bubbled northward, clashing with the weather front draped from near Chicago to just north of D.C., thunderstorms erupted. They grew in coverage and intensity as they raced southeast, powered by the roaring upper level winds and fueled by the record-setting heat and oppressive humidity in their path.

The derecho of June 29, 2012 is also considered the largest of its kind. The Weather Gang describes this one as an event that “is likely to go down as not only one of the worst on record in Washington, D.C. but also along its entire path stretching back to northern Indiana.”

WJLA Meterologist Mike Stinneford echoed a similar observation to WTOP:

“This was a very large derecho,” says Stinneford. “This is probably one of the biggest ones we’ve ever seen … probably one of the worst storms ever in D.C. outside of a hurricane or the type of the damage you see from a major winter storm.”

The major takeaway from this storm from a meteorlogical perspective was the size of its swath, he says.

“Outside of a hurricane, you will never see wind damage this widespread or this long-lived unless you had a land-falling hurricane.”

The derecho left millions of customers without power during a day with, once again, extreme temperatures. The damage could take days to repair. The event even claimed at least five lives in the District, including a 67-year-old man, reported by WJLA as Ghafoorian Mohammad, who was electrocuted by a live wire outside his Northwest home. The dangerous conditions the storm caused even prompted D.C., Virginia and Maryland to declare a state of emergency.